Credit value: 10
27
Spreadsheet
modelling
The spreadsheet and the word processor were the business applications
that started the personal computer revolution, and they remain the
most popular and useful applications. The popularity of spreadsheets
comes from their ability to carry out financial calculations with ease.
But the software is very versatile and, in addition to its financial and
mathematical uses, it can be utilised for a number of other applications
such as maintaining simple lists and databases, presenting data as charts
and graphs, and creating complex tables of text and numbers.
Spreadsheets are also widely used in business, science and other areas to create
models. A spreadsheet model helps you answer a question, such as ‘How much will it
cost me to run a car?’, or predict a likely future outcome, such as ‘How much profit will
my business make next year?’ For these reasons, they are a powerful tool for planning.
This unit links closely with Unit 9: Customising software, which covers improving
spreadsheets and other applications software by introducing templates,
shortcuts and macros.
Learning outcomes
After completing this unit you should:
1. know what spreadsheets are and how they can be used
2. be able to develop spreadsheet models
3. be able to test and document spreadsheet models.
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BTEC’s own resources
Assessment and grading criteria
This table shows you what you must do in order to achieve a pass, merit or distinction, and where
you can find activities in this book to help you.
To achieve a pass grade the
evidence must show that you
are able to:
To achieve a merit grade the
evidence must show that, in
addition to the pass criteria,
you are able to:
To achieve a distinction grade
the evidence must show that, in
addition to the pass and merit
criteria, you are able to:
M1 refine a spreadsheet model
D1 evaluate a spreadsheet
P1 describe the uses of
spreadsheet software
See Assessment activity
27.1 on page 8
P2 explain why spreadsheets
may need to be converted to
alternative file formats
See Assessment activity
27.1 on page 8
P3 develop a spreadsheet model
to meet particular needs
See Assessment activity
27.2 on page 35
by changing rules and values
See Assessment activity
27.3 on page 40
P4 use simple formulae and
D2 use automated features in the
functions to process information
See Assessment activity
27.2 on page 35
P5 use data types and formatting
to present information
See Assessment activity
27.2 on page 35
P6 use appropriate tools to
present data
See Assessment activity
27.3 on page 40
P7 test a spreadsheet to ensure
that it is fit for purpose
See Assessment activity
27.4 on page 42
P8 produce user documentation
for a spreadsheet model
See Assessment activity
27.4 on page 42
2
model suggesting further
refinements
See Assessment activity
27.2 on page 35
spreadsheet model
See Assessment activity
27.4 on page 42
M2 justify choice of tools for
presenting data
See Assessment activity
27.3 on page 40
M3 analyse and interpret data
from a spreadsheet model
See Assessment activity
27.3 on page 40
Unit 27 Spreadsheet modelling
How you will be assessed
This unit is internally assessed. You will provide a portfolio of evidence to show
that you have achieved the learning outcomes. Your portfolio of evidence can
be supplied in many formats including electronically as well as paper-based. The
grading grid in the specification for this unit lists what you must do to obtain pass,
merit and distinction grades. The Assessment activities in this unit will guide you
through tasks that will help you to be successful in this unit.
Your tutor will tell you exactly what form your assessments will take, but you could
be asked to produce:
•
•
written documentation, for example
a short report, spreadsheet files
practical work
• a pamphlet or leaflet
• annotated screenshots
• a presentation.
Feroz Kapoor, a 15-year-old
BTEC First learner
I really enjoyed this unit. Spreadsheets are amazing because there’s
so much they can do and there’s always more to learn about them. I’d
already learned the basics of using spreadsheets before I did this unit,
so I was worried that I’d find it a bit boring. But we didn’t spend a lot
of time on the basics. The unit is more about building spreadsheets which
answer the sort of questions you might come across in business. In the future I
really want to run my own business, so for me learning about how to use a spreadsheet to
plan and forecast things like business costs and profits was really interesting.
The assessments for this unit were quite hard, especially the merit and distinction ones. I had
particular trouble justifying my choice of a chart for presentation data (M2) and evaluating
my spreadsheet and suggesting refinements (D1). Our tutor suggested we got together in
small groups and discussed each other’s spreadsheets. It turned out it was much easier to
suggest improvements on other people’s spreadsheet models than on our own. I think we
thought our own ones were perfect! We also came up with some good ideas for justifying
spreadsheets – by comparing the numerical data and the chart, you could see how much
easier it was to make sense of the data from the chart.
Over to you!
•
Do you know something about how to use spreadsheets already?
•
What sort of things should you think about when you need to justify
using a certain feature?
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BTEC’s own resources
1. Know what spreadsheets are and how
they can be used
Start
Warmup
up
Ideas for spreadsheet models
A model is something that mimics real life. With a model you can make predictions
or plans and try to answer questions. There are lots of things you might want to
model, such as ‘How many merit grades do I have to get on this course to get a
merit overall?’ or ‘How many matches does my team need to win to come top
of the league?’ We tend to think of spreadsheet models in a business or financial
context, but there are many more areas where creating a model is useful or
interesting.
In a group, discuss the sorts of models you would like to create.
•
Choose one idea for a model from those you discussed.
•
What kind of data will you need to build your model?
•
Could you use a spreadsheet to build your model?
Key terms
Workbook – a spreadsheet file, which is
made up of a group of worksheets that
are saved together in a single file.
A spreadsheet workbook is made up of tables known as worksheets,
with rows and columns making up individual cells. The columns are
labelled with letters of the alphabet and the rows are numbered. Each
cell has an address, which is its column letter and row number.
Worksheet – a page of tables used to
create a spreadsheet.
Figure 27.1: A worksheet
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Unit 27 Spreadsheet modelling
Activity: Spreadsheet size and
quantity
•
What happens after column Z?
•
How many rows and columns does a worksheet have?
•
How many cells does this provide?
If you want a real challenge, find out what other limits there are in
Microsoft® Excel®. For example, how many different worksheets can
you have in one workbook (spreadsheet file)?
By default, a spreadsheet has three worksheets, but you can add more
if required. A single spreadsheet workbook can, therefore, hold a very
large amount of data.
There are basically three things you can enter in a worksheet cell:
•
Text can be formatted in a variety of ways, for example you can
change its font, size or colour.
•
Numbers can be formatted depending on what kind of numbers
they are. For example, you can choose the Currency format, which
will display a number with a currency symbol in front (£ in the UK)
and two digits after the decimal point. You can also format the
appearance of numbers in the same way as you can text. We’ll look
at formatting in more detail later.
•
Formulae are what make spreadsheets really useful. A formula
carries out a calculation on numeric values in other cells. We’ll also
look at formulae in more detail later.
Many people also use spreadsheets as simple databases to store flat file
data, i.e. single database tables.
1.1 Uses of spreadsheets
Spreadsheets are very flexible and are used for all sorts of applications.
They are most commonly used for storing, manipulating and analysing
numeric data. The table structure of the worksheet makes it ideal for
storing values that represent something, such as the number of sales
made in each month of the year or a learner’s mark in an assignment.
Key terms
Formulae – used to carry out
calculations in a spreadsheet. A formula
must begin with an equals sign (=) and
can use either actual values (numbers) or
references to cell addresses.
Value – a number which can either
be a fixed number entered by the
spreadsheet’s user or a number that is
calculated by a formula.
Activity: Spreadsheet uses in
industry and commerce
•
Do you know anyone who uses spreadsheets in their business? Find
out what they use them for.
•
Do your tutors use spreadsheets for keeping track of your progress
on this course? Look into how staff at your centre of learning use
spreadsheets and find some examples of the spreadsheets they use.
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BTEC’s own resources
Case study: NEAL training
NEAL training is a small private training company
that offers vocational training for job seekers under
contract to local job centres. They need to keep track
of their learners’ attendance and punctuality, and
meet the targets set by the organisations that fund the
training. Alice Haynes, the training manager, uses a
spreadsheet to keep track of this data; an example is
shown in Figure 27.2.
The spreadsheet uses formulae to calculate the weekly
percentages for attendance and punctuality for each
of the training programmes that the company runs. It
also uses an If function (see pages 16–18) to highlight
the programmes that have below-target attendance
or punctuality. Charts are drawn from the data to help
identify trends and problem areas.
Alice says: ‘Although in some ways this kind of data
might be better suited to a database application, it’s
quicker and easier to set it up using Excel®. Also, my
director prefers me to use spreadsheets to record
information because he understands them well. The
charts are useful because they make it easy to see at a
glance where the serious problems lie.’
1. What reasons does Alice give for preferring to
use a spreadsheet rather than a database?
2. What disadvantages might there be to using
a spreadsheet rather than a database in this
application?
3. Does your tutor collect or use statistics on
attendance and punctuality? If so, how do they
store and present that data?
Figure 27.2: Weekly attendance and punctuality spreadsheet
Presenting and interpreting information
Large quantities of data can be stored in a spreadsheet. But lots of
numbers can be difficult to interpret, making questions such as ‘Is the
value of sales we make each month increasing or decreasing?’ difficult to
answer. Therefore, spreadsheets provide tools, such as charts and graphs,
to enable you to present data in different ways and make interpretation
easier. It is much easier to see trends and to identify relationships between
data when looking at a graph than it is by looking at ‘raw’ figures.
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Unit 27 Spreadsheet modelling
Calculations
Spreadsheets are also useful for carrying out calculations repetitively
and, as long as the initial formulae are correct, you can rely on the
spreadsheet to be accurate. This can be useful in spreadsheets such as
monthly salary calculations.
List management
The ability to manage and manipulate large lists of data is also one of
the spreadsheet’s strengths. This facility allows you to use a spreadsheet
like a simple database.
1.2 Alternative formats
In addition to the standard format for saving spreadsheets (for Excel®
this is known as the xls format because the file extension is .xls), there
are a number of alternative formats you can use for different purposes.
These include:
•
PDF (Portable Document Format). When you save a spreadsheet
as a PDF it can be viewed but not edited by others. The PDF
format is very widely used, so it is ideal if you want to publish your
spreadsheet online and allow anyone to download and view it (even
if they don’t have a copy of Microsoft® Office®).
•
HTML (Hyper Text Markup Language). Saving your spreadsheet
as HTML means you could include the spreadsheet as part of a web
page. As with PDF, your spreadsheet can be viewed but not edited
in this format.
•
CSV (Comma Separated Values) file. This is a text file with the
contents of each cell separated by a comma. This format can be
used to import the spreadsheet data into a database application.
•
TXT file. This is a plain text file.
•
XML file. This is an industry standard format so is useful when you
need to export spreadsheet data to other applications (especially
non-Microsoft® ones) such as a database.
When you save your spreadsheet in any of these formats, the formulae
are converted to values. This means you have created a ‘final’ version of
the spreadsheet.
Did you know?
To find out more about the different
file formats for saving spreadsheets,
use the Help facility in Excel® and
search for ‘File formats’.
Did you know?
You can download a free PDF viewer
from the Adobe® website. To access
this site, go to Hotlinks and click on
the link for this unit.
Just checking
1.
2.
3.
4.
What is the difference between a workbook and a worksheet?
Why might you want to save a spreadsheet as a PDF file?
Name one tool provided by spreadsheets to help analyse and interpret data.
How are the rows and columns of a worksheet identified?
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BTEC’s own resources
Assessment activity
27.1
PLTS
Researching the different uses of
spreadsheets will provide evidence
that you are an independent
enquirer.
Functional skills
P1 P2
You have recently taken a job as a trainee IT support specialist
at a university. The IT manager has asked you to write a guide
for non-technical lecturers about how they can use spreadsheets
for different tasks P1 . The guide also needs to explain why
spreadsheets may need to be converted to other file formats P2 .
Grading tip
•To make sure you cover all the required material, check the
unit content in the specification under Learning outcome 1.
Writing the guide will provide
evidence for your Functional English
skills in writing.
2. Be able to develop spreadsheet models
2.1 Formulae
Key terms
Formula bar – in Excel® this is located
under the Ribbon and shows the formula
of the current cell (if it contains one). The
cell itself shows the result of the formula.
Cell pointer – indicates the current cell.
Before you can enter anything into a cell,
you must move the cell pointer using
the cursor keys or the mouse to the cell
where you want to make the entry.
Figure 27.3: The formula bar
8
Formulae provide the real power in spreadsheets. They are used to carry
out calculations. The key thing to remember is that, if you want to enter
a formula in a cell, it must begin with an equals sign (=). Let’s look at a
simple example. The following formula will add together two numbers:
=6+8
If you type this formula into a spreadsheet cell, the cell will display the
answer: the number 14. That’s because the cells in the worksheet display
the result of the formula; the formula itself is displayed in the formula
bar when the cell pointer (the thick black box around a cell) is located
on that cell (see Figure 27.3).
Unit 27 Spreadsheet modelling
The cell pointer can be moved by the mouse by clicking in the cell
where you want it located, or by using the cursor keys to move one cell
at a time.
Entering actual values in a formula is fine, but it is much more useful to
be able to enter a cell address instead. If we enter the value 6 in cell
B5, we can change our formula to the following:
Key term
Cell address – the method used to refer
to the contents of a particular cell in a
formula. The cell address consists of the
column letter and row number of the cell.
=B5+8
You can edit the formula by clicking in the formula bar, deleting the
number 6 and typing the cell address B5. The result of the formula (in
C5) will still be 14. However, if we make a change to the value in B5, e.g.
entering 12 instead of 6, the formula in C5 automatically recalculates the
new result. Figure 27.4 shows the changed formula.
Figure 27.4: Formula using cell address
You can write a formula to add, subtract, divide, multiply and raise to
power. The symbols you need to use are shown in Table 27.1.
Table 27.1: Arithmetic symbols
Symbol
Meaning
+
Add
-
Subtract
*
Multiply
/
Divide
^
Raise to power
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BTEC’s own resources
2.2 Spreadsheet models
A financial spreadsheet model
Let’s look at a simple example of how a spreadsheet model can be
used. Imagine you are saving money to buy a car that costs around
£1,500. You want to buy the car in about nine months’ time, but you
don’t know how much you’ll need to save each month to reach your
target. The spreadsheet shown in Figure 27.5 shows the basic layout.
Figure 27.5: ‘Saving for a car’ spreadsheet
The amount saved each month in B4 is a number, and so is the number
of months in D4. These two amounts need to be multiplied together to
give the total amount saved. A formula is needed in F4, which is:
=B4*D4
The target amount in H4 is entered
as the value of 1500. The shortfall (or
surplus) is the difference between the
amount saved (in F4) and the target
amount in H4. The following formula
will calculate the shortfall:
=H4-F4
Figure 27.6 shows the spreadsheet
completed, with example values in
cells B4 and D4.
Figure 27.6: Completed spreadsheet
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Unit 27 Spreadsheet modelling
This demonstrates one of the main benefits of spreadsheets – as the
formulae are constantly recalculated, we can change the amount saved
each month (in B4) and the number of months (in D4) to investigate
different possibilities. This kind of spreadsheet is sometimes called a
‘What if...?’ spreadsheet, since we can use it to answer questions such as:
•
What if you could only save £75 a month? Changing the number of
months shows it will take 20 months to save for the car.
•
What if you choose a cheaper car, costing £900? Keeping the
number of months as nine, how much will you need to save each
month?
A budget spreadsheet
Another common type of spreadsheet is the budget spreadsheet. In
this type, columns of figures representing income or outgoings, to or
from various sources, are totalled up. Imagine you want to estimate the
monthly cost of running a car over four months. Figure 27.7 shows a
spreadsheet set up to calculate monthly costs. The values entered have
been formatted as currency. You can do this either by entering a £ sign
in front of each value as you type it or by highlighting all the cells with
the cell pointer (by dragging across them with the mouse pointer) and
clicking the Currency button in the Formatting toolbar.
Figure 27.7: Monthly cost spreadsheet
Since the costs of petrol and insurance stay the same each month, you
can enter the value once then copy and paste it into the other cells. If
you highlight all the cells where you want to paste the value, you can
then paste multiple copies in one go.
Relative cell referencing
To add up the costs for the month of January, you could enter the
following formula:
=C3+C4+C5
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BTEC’s own resources
Once this formula has been entered, it can be copied as well. However,
when you copy formulae, something very important happens. In other
applications, when you copy and paste something it stays the same,
but not with spreadsheet formulae. Instead, the cell addresses change
relative to the cell into which they are copied.
Key terms
Relative cell referencing – a cell
address that changes when it is copied
to a different cell.
Absolute cell referencing – a cell
address that does not change when you
copy it.
When we copy this formula along the columns (i.e. into columns D,
E and F), the column letters in the formula change although the row
numbers remain the same. This is exactly what we want to happen – it
means the formula adds up the correct values for each month. The
effect is known as relative cell referencing. Later in this unit we will
look at situations where you do not want the cell addresses to change
when you copy a formula – this is called absolute cell referencing (see
pages 21–23).
Figure 27.8 shows the completed spreadsheet.
Figure 27.8: The completed spreadsheet
Because spreadsheet software allows you to copy both values and
formulae simply, this makes it easy to create large spreadsheets. Since
the cell addresses in the formulae are automatically adjusted as you
copy them, you only have to enter them once. Many financial budget
spreadsheets include figures for a whole 12 months, i.e. one year. If you
only have to enter a formula to add up a monthly total once, instead of
12 times, this obviously saves a lot of time.
Complex formulae
Mathematical precedence
Mathematical precedence means the order that calculations are done
in a complex formula. For example, what do you think the result of the
following formula would be?
=5+2*2
You might imagine that the result would be 14, because 5+2 is 7, then
multiplied by 2 is 14. However, calculations in spreadsheets are not
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Unit 27 Spreadsheet modelling
done left to right. They are done based on the order of mathematical
precedence, and multiplication is done before addition. So the result
would be 2 multiplied by 2 is 4, then add 5 is 9.
The order of mathematical precedence is shown in Table 27.2.
Table 27.2: The order of mathematical precedence
Order
Function
Symbol
1
Brackets
()
2
Raise to power
^
3
Divide
/
4
Multiply
*
5
Add
+
6
Subtract
-
Did you know?
Note that anything in brackets is done first, so to get the answer 14 from
the previous example, the formula would need to be:
=(5+2)*2
2.3 Functions
In addition to the arithmetic operators we have used so far, formulae
can also include functions that carry out a wide range of mathematical
calculations. Excel® has hundreds of functions, but we’ll look at just a
few of the most useful ones.
In Figure 27.9, Column A has been
widened to fit the names of the
games. You do this by moving the
mouse pointer into the grey title bar
of the columns, between the column
you want to widen and the next one
(between columns A and B in this
case). When the two-headed arrow
mouse pointer appears, you click and
drag the line to the right to widen
column A.
The Sum function
The Sum function is one of the most widely used
functions. It is used to add up a column or row of
values. It is used so often that there is an AutoSum
button on the Home tab of the Ribbon that
automatically creates a formula using the Sum function.
First, let’s look at how to use the Sum function
manually, so that we can understand how it works
before looking at the automatic version.
Imagine you have a spreadsheet like the one shown
in Figure 27.9. This spreadsheet might be used by a
games shop. It lists all the games they have, the price
and the number in stock.
To add up the total number of games in stock, you
could enter a formula in C14 that adds each cell
one by one, but this would be a long-winded way of
doing it. The Sum function is much easier to use –
you only need to enter the starting cell (C4) and the
ending cell (C14) in the list to be added, separated by
a colon, like this:
=SUM(C4:C13)
Figure 27.9: Games Store spreadsheet
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BTEC’s own resources
If you use AutoSum button in the Ribbon, you don’t have to type
anything. Just click in the cell where the formula should go (C15) and
click the AutoSum button. Excel® looks for a row or column of numbers
above or to the left of the currently selected cell and creates the
formula using the Sum function for you (see Figure 27.10). It displays
the formula for you to check, and when you press the Enter button it
completes the automatic creation of the formula.
Figure 27.10: The AutoSum button
Activity: Using the AutoSum button
Column D on the spreadsheet shown in Figure 27.10 is meant to display
the value of the games in stock (the price multiplied by the quantity).
Enter the correct formula in D4 and copy it down to D14, then use the
AutoSum button to calculate the total value of the games in stock.
The Min, Max and Average functions
Key term
These statistical functions work in a similar way to the Sum function, but
there is no Ribbon button to create them automatically.
Statistics – the science of making sense
of data.
To find the maximum price of a game you would enter the following formula:
=MAX(B4:B13)
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Unit 27 Spreadsheet modelling
The Min function works in the same way and displays the minimum
value in the range.
The Average function displays the average value (or mean) across
the range.
Activity: Finding minimum,
maximum and average values
Enter the formulae to calculate the minimum, maximum and average
prices of the games. When complete, the spreadsheet should look
like Figure 27.11.
Did you know?
Figure 27.11: Spreadsheet with minimum, maximum and average prices
The Count function counts the cell
only if it contains a number. If the cell
contains text it will not be counted.
The Count and Countif functions
Count is another simple statistical function. It counts the number of cells
within a range that contain numbers. For example, if we use the Games
Store spreadsheet shown above and enter the formula =Count(C4:C14),
we will get the result 11. That’s because there are 11 cells in the range
that contain a number (all of them in this case).
The Countif function adds the ability to count only the values in a
range that meet certain criteria. The criteria can be a single value (such
as 3), a text value (such as “Yes”) or an expression using a comparison
operator (such as “>10”). Note that expressions and text values must be
enclosed in double quotation marks.
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BTEC’s own resources
Table 27.3 shows the comparison operators you can use.
Table 27.3: Comparison operators
Symbol
Meaning
=
Equal to
>
Greater than
<
Less than
>=
Greater than or equal to
<=
Less than or equal to
<>
Not equal to
For example, the Games Store needs to reorder games when the
quantity in stock has fallen below 6. We can show the number of games
that need reordering using the formula:
=COUNTIF(C4:C14,“<6”)
Activity: Identifying excess stock
The Games Store manager is thinking of offering a discount on the
price of games where there are more than 10 in stock. What formula
would tell you how many games that applies to?
The If function
The If function is more complex than the statistical functions we have
looked at so far, but it is also more powerful. It allows you to change
what the spreadsheet does depending on the outcome of some kind of
test. For example, if the value in a particular cell is greater than 10, you
can display a message or do a calculation; whereas if the value is less
than 10, you can display a different message or do a different calculation.
First, let’s look at the basic structure of the If function. This has three
parts within the brackets that follow the function name:
=IF(test, action if test is true, action if test is false)
The first part – the test
The test can simply be comparing the contents of a cell with a value
or with text. For example, C4=10 means ‘Does C4 contain 10?’ and
C4=“Yes” means ‘Does C4 contain the text Yes?’ Alternatively, the test
can use the comparison operators we have looked at with the Countif
function. For example, C4>10 means ‘Is C4 greater than 10?’
The second and third parts – what to do as a result of the test
The next two parts of the function describe what to do if the result of
the test is true and what to do if it is false. These actions can also be a
simple value or some text, for example:
=IF(C4>10,“Too much”, “Not enough”)
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Unit 27 Spreadsheet modelling
In this example, if the value in C4 is greater than 10, then the text “Too
much” is displayed in the cell that contains the If function. If the value in
C4 is not greater than 10, then the text “Not enough” is displayed.
These actions could also be a calculation, for example:
=IF(C4>10, C4+2, C4-2)
Here, if the value in C4 is greater than 10, then that value has 2 added
to it and the result is placed in the cell that contains the If statement. If
the value in C4 is less than 10, then 2 is subtracted.
The If function in use
Now let’s look at a real example of the If function in use. Remember the
Games Store spreadsheet we used to demonstrate the other functions.
On page 16 we used the Countif function to show the number of
games that need reordering because the quantity in stock has fallen
below six. However, this function does not tell us which games need
reordering, only how many there are. With the If function we can display
a message next to the game telling us to reorder it.
We start off by entering the formula using the If function in cell E4. The
test is ‘Is C4 (the quantity) less than 6?’ The action, if the test is true (i.e.
C4 is less than 6) is to display the text ‘Reorder’. The action if the test is
false (i.e. C4 is 6 or more) is to display a dash. The formula is shown in
Figure 27.12.
Figure 27.12: The formula using the If function
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BTEC’s own resources
Once you have entered the formula in E4, copy it down through cells
E5 to E14. You can do this by copying and pasting or you can use the
copy box on the current cell pointer. This is the small black box on the
bottom-right corner of the current cell pointer, as shown in Figure 27.13.
Figure 27.13: The cell pointer copy box
When you move the mouse pointer over the copy box, it changes to a
black cross. If you drag down through the cells that you want to copy
into (E5 to E14) with the black cross mouse pointer, the formula will be
copied for you. The completed spreadsheet is shown in Figure 27.14.
Figure 27.14: The completed spreadsheet
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Unit 27 Spreadsheet modelling
Using AND and OR
The If function used in the previous example was able to test only one
cell (C4). However, there may be situations where you want to test the
values in two or more cells and do something if both the tests are true.
The AND logical operator
Let’s look at an example. The Games Store wants to discount (reduce)
the price of any game that costs over £26 if there are 10 or more
in stock. Here there are two tests that need to be done (>£26 and
>=10). We only want to discount the game if both the tests are true,
so we use the AND logical operator. Figure 27.15 shows the modified
If function.
Figure 27.15: If function using AND
The tests are now preceded by AND,
like this:
AND(C4>=10,B4>26)
If the test is true (i.e. we have more
than 10 in stock and the price is over
£26), then the price in B4 has £10
subtracted from it. Otherwise the
price is kept the same. The complete
formula looks like this:
=IF(AND(C4>=10,B4>26),B4-10,B4)
Once the formula is complete you can
copy it down the rest of the column.
If you check carefully, you should see
that the prices have been reduced
on the games that meet the two test
criteria, as shown in Figure 27.16.
Figure 27.16: The new reduced prices (highlighted in red)
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The OR logical operator
Using the AND logical operator means that both tests must be true for
the true action to be carried out. However, if you use the OR logical
operator, then the true action will be carried out if either one of the
tests is true.
If we modify the formula just entered to use OR, then the price of the
game will be reduced if there are 10 or more in stock or if the game
costs over £26. This is shown in Figure 27.17. Note that now the prices
of almost all the games are reduced, since most of them meet one or
other of the test criteria.
Figure 27.17: Using the OR logical operator
Activity: Other worksheet
functions
Excel® has many more functions than the few we have looked at here.
Find out more about the other functions by searching in Help for ‘list
of worksheet functions’.
If you want a real challenge, find out how the following worksheet
functions can be used and create example spreadsheets that use
them:
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•
Today
•
Rand
•
Vlookup
•
Weekday.
Unit 27 Spreadsheet modelling
2.4 Entering and editing data
Absolute and relative cell referencing
We’ve already introduced the concept of relative cell referencing.
This is the way cell addresses in formulae change when you copy
them. However, there are some situations when you don’t want the
cell address in a formula to change when you copy it. The following
example demonstrates why.
We’ll use the Games Store spreadsheet again, but for simplicity we’ll
leave out the If function formulae. This time we want to have a sale and
reduce all the prices by between 5 and 15 per cent. But we want to do
a bit of ‘What if...?’ experimentation to see how different percentages
will affect the total value of our stock. Figure 27.18 shows the modified
version of the spreadsheet with an example percentage reduction
already entered in cell B16.
Did you know?
To enter a value as a percentage,
simply type the % sign after the
number.
Figure 27.18: Games Store sale spreadsheet
We need to enter a formula in E4 to reduce the existing price in B4 by
the percentage in B16. First we multiply these two values together to
get 10 per cent of the current price (£3.15). Then we need to subtract
that from the current price to get the sale price. The formula we need is:
=B4–B4*B16
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We don’t need brackets here, as the multiplication is done first anyway.
If we now copy this formula down the rest of the column we find that a
problem occurs, as shown in Figure 27.19.
Figure 27.19: Copying the formula
Did you know?
Pressing the F4 key (function key on
the top of your keyboard) after you
have entered a cell address will insert
the $ sign in front of the column
letter and row number for you.
Figure 27.20: An absolute reference
The 10 per cent reduction has worked correctly on the first price, but
none of the other prices have been reduced. If we look at the formula
in E5 we can see why (look in the formula bar in Figure 27.19). Relative
referencing has changed the original B4 in the formula to B5 – this is
correct as the value in B5 is the price of the next game. But it has also
changed B16, the cell with the percentage reduction, to B17, which
contains nothing. We don’t want that part of the address to change
when we copy the formula – we want it to stay fixed as B16. Fixing a cell
address so that it does not change is called absolute referencing.
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Unit 27 Spreadsheet modelling
To make that part of the formula
use absolute referencing, we need
to return to the formula in E4 and
edit it in the formula bar. Click in
front of B16 then enter a dollar ($)
sign in front of the B and another $
sign in front of the 16. It should now
read $B$16, as shown in
Figure 27.20.
Now, if you copy this formula down
through the column, the B4 part of
the formula will change (because of
relative referencing) but the B16 part
will not change (because of absolute
referencing). This new version of the
formula will display reduced prices
for all the games, as shown in
Figure 27.21.
If you wanted to fix only the row or
the column address, instead of both,
you can do this by inserting the $
sign in front of the column letter or
row number only.
Figure 27.21: Reduced prices for all games
Activity: Using absolute
referencing
To complete the spreadsheet, add a formula in column F to calculate
the value of the games with their reduced prices (quantity multiplied
by sale price). Then use the AutoSum button to provide a new total
value of the stock in cell F14.
•
What is the maximum percentage sale reduction that can be
given while keeping the total value of the stock above £2000?
Autofilling cells
Spreadsheet software contains lots of features to make creating
large spreadsheets easy; one of those features is AutoFill. Many
budget spreadsheets have the months across the top of the columns
(like the car cost calculator we created on pages 10–12). Instead of
having to type each month, you can just type the first month. (It doesn’t
have to be January – you can start with any month – and you can use
the abbreviated version, such as Jan, if you wish.) Then use the cell
pointer copy box (see page 8) to copy the cell across as many cells as
you need. AutoFill will enter the month names for you, as shown in
Figure 27.22.
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Figure 27.22: Using AutoFill to complete month names
You can use AutoFill to enter the days of the week in the same way – either
the full names (e.g. Monday) or the abbreviated versions (e.g. Mon). You
can also enter a date (e.g. 04/07/2011) and AutoFill will fill in subsequent
dates for as many days as you wish.
AutoFill can also complete a sequence of numbers or dates if you show it
what sequence you want. For example, to number cells sequentially, just
type 1 in the first cell you want to number, then 2 in the next one. Then
select these two cells by dragging across them
with the white-cross mouse shape, click and drag
on the copy box and keep dragging for however
many cells you want to number. AutoFill will fill in
the numbers for you.
Another example is if you want a series of cells
to show the dates on each Monday for several
weeks. Just enter the first two dates – for example
22 March 2010 is a Monday, and the following
Monday is 29 March 2010 – in two cells that are
next to each other. Select these cells and then use
the copy box to list as many Monday dates as you
require (see Figure 27.23). This can make creating
a timetable or schedule easy, as you don’t need to
look up each date.
Figure 27.23: Using AutoFill to enter dates
2.5 Automations
Linking spreadsheets
One of the benefits of having multiple worksheets in one spreadsheet is that
you can link information between the worksheets. You can see the benefits
of this by looking at some examples. There are two ways to create links:
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•
enter links between worksheets as formulae
•
use Paste Link.
Unit 27 Spreadsheet modelling
How to... Link spreadsheets using manual links
Imagine you have two computer games shops – one in Luton and
one in Watford. You keep a record of each shop’s sales on two
worksheets in the same spreadsheet. The spreadsheet is shown in
Figure 27.24, with the Luton shop worksheet currently displayed.
The worksheet for the Watford shop is set up in exactly the same
way – only the sales figures are different.
The worksheets have been given names (look at the tabs at
the bottom of the worksheets), rather than just Sheet1, Sheet2,
etc. (You can do this by double-clicking on the sheet name and
typing in the name you want.)
Now we are going to create a third worksheet, called Total
Sales, which will show the combined total sales from both the
Luton and Watford shops. The basic layout of this worksheet is
shown in Figure 27.25.
Figure 27.24: The Games shops sales spreadsheet
To copy the values from the other worksheets:
•
First click in cell B4, which is where the January total from
the Luton shop will go.
•
Type an equals sign to start a formula.
•
Now click on the Luton shop worksheet name to swap to
that worksheet.
•
Click in B7 on the Luton shop worksheet (which contains the
January total). Notice that, on the formula bar, the address
of that cell in that worksheet (‘Luton shop’!B7) has been
entered. (The worksheet name is in single quotes followed
by an exclamation mark and the cell name. This is the
format of a cell address that contains a worksheet name.)
(See Figure 27.26.)
•
Now press Enter to complete the formula.
•
You will now be returned to the Total Sales worksheet, with
the value from the Luton shop worksheet displayed. This
value is linked with the Luton shop worksheet – if a change
is made to that value on the Luton shop worksheet, it will
change here too.
•
Now copy the formula that you created for the Luton Shop
January sales total across to February and March (cells C4
and D4). Relative addressing works in just the same way
as it does with cells that are on the same worksheet – the
formula adjusts the cell addresses to pick up the correct
monthly totals.
•
Insert the totals for the Watford shop in the same way –
create a formula that links with the Watford shop worksheet
for January then copy the formula across for February and
March. The grand totals can be completed using a simple
formula (e.g. =B4+B5 for January, and so on).
•
The completed sheet should look like Figure 27.27.
Figure 27.25: Total Sales worksheet
Figure 27.26: Linking the worksheets
Figure 27.27: The completed Total Sales sheet
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How to… Link spreadsheets using Paste Links
Paste Link provides an alternative method for creating links between
worksheets.
•
Click on the cell containing the formula you want to copy (e.g. B7 in
the Luton worksheet) and choose Edit then Copy (or click the copy
icon in the Ribbon).
•
Now go to the cell where you want the formula to be copied into
(e.g. B4 in the Total Sales worksheet) and choose Edit then Paste
Special. This will display the Paste Special dialog box.
•
Click the Paste Link button and the link formula will be inserted.
However, note that the cell references have been made absolute, so
the formulae cannot be copied as described above. So although Paste
Link provides an easy way to create links between worksheets, in this
example it would be easier to create the linking formulae manually.
Macros
Macros allow regularly used functions to be automated. A task that might
take several keystrokes or menu selections can be simplified by creating
a macro that carries out the task with a single mouse click. The subject of
macros is covered in Unit 9: Customising software, pages 164–169.
2.6 Refining spreadsheet models
Improving efficiency
Excel® provides many shortcut key combinations to make it easy to
move around large or multiple worksheets. Some of the more useful
ones are listed in Table 27.4.
Table 27.4: Commonly used shortcut keys
Shortcut key
Effect
For moving around a worksheet
Key term
Data region – an area of cells that
contains something and is surrounded
by empty cells or the edge of the
worksheet.
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Ctrl + End
Moves cell pointer to the last used cell in a
worksheet (bottom-right cell)
Ctrl + Home
Moves cell pointer to cell A1
Home
Moves cell pointer to the beginning (i.e.
column A) of current row
Page Down
Moves one screen down
Page Up
Moves one screen up
Selecting cells
Ctrl + A
Selects the current data region
Ctrl
Allows you to select non-adjacent areas (i.e.
areas that are not next to each other)
Unit 27 Spreadsheet modelling
Table 27.4: Contd.
Moving between worksheets
Ctrl + Page Up
Move to next worksheet
Ctrl + Page Down
Move to previous worksheet
Formatting
Ctrl + Shift + $
Applies currency format
Ctrl + Shift + %
Applies percentage format
There are many more shortcut keys, but it can be difficult to remember
them all unless you use them often. You can find out about them all by
searching the Help menu in Excel®.
2.7 Combining information
There are some situations when you will want to select information
created in Excel® and insert it into another software package, such as a
Word® document. For example, you may wish to do this if you need to
produce a financial report.
Simple copy and paste
The simplest way to insert data into a Word® document is to copy the
required cells from Excel® and paste the data into Word®. Once pasted
into a Word® document, worksheet cells will become a Word® table and
can be edited in the normal way. An example is shown in Figure 27.28,
but as you can see, the columns of the table need widening to display
the data on one line.
Cells pasted in this way are no longer connected with the original
spreadsheet.
Figure 27.28: Excel® spreadsheet
cells pasted into a Word® document
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Retaining a link to the original data
It’s also possible for the pasted cells in the Word® document to remain
linked with the original spreadsheet, so that changes made in the
spreadsheet will be reflected in the pasted cells in the Word® document.
How to… Retain a link to the original data
Copy the cells from Excel® and switch to the Word® document.
•
Select the Home tab in the ribbon and click the
arrow under the Paste icon.
•
From the menu that appears choose Paste Special.
This will display the Paste Special dialog box (see
Figure 27.29). Click the Paste Link button.
•
Select the document type Microsoft Office
Excel Worksheet Object from the list box then
click OK.
•
The cells will be inserted in the Word® document
as before, but not as a Word® table. Rather, the
cells behave as a graphic image.
•
To edit the cells, double click on them and the
original spreadsheet will open up in Excel® but
inside Word®.
Figure 27.29: The Paste Special dialog box
2.8 File handling
You must, of course, save the spreadsheet file you produce. Normally
you will save the spreadsheet as an Excel® file, but in some situations
you may want to export the file in an alternative format, for example to
use the spreadsheet in a database or web page.
Did you know?
It’s not a good idea to use the default
name such as Book1, as it tells you
very little about what the spreadsheet
contains. It is much better to think of
a more descriptive name that gives
some clue to the contents of the
spreadsheet. For example, you might
call a monthly budget spreadsheet
Budget for Jan 11.
How to… Save a spreadsheet file
Save a file in Excel® by going to the Office menu and choosing Save. To
save an existing file with a different name, choose Save As. Alternatively,
you can use the Save button in the Quick Access toolbar.
If the spreadsheet has not been previously saved, or you choose Save
As, you will see the Save As dialog box. You will be offered a default file
name such as Book1.xls.
If you want a different format for your spreadsheet, you can select the
format you want from the drop-down list from the Save as type box on
the Save As dialog box.
When you are creating lots of spreadsheets and other files, it’s a good
idea to create a folder structure to keep related files together.
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Unit 27 Spreadsheet modelling
2.9 Presenting data
So far we’ve kept our spreadsheets fairly plain, but there are many
options that allow us to format the data in a spreadsheet, thereby
improving the way it is presented.
Data types
There are several different ways that numbers can be formatted
in Excel®:
•
Default number format. This is the format you get when you enter
plain numbers.
•
Comma format. This numeric format will add two digits after the
decimal point and a comma after the thousands. There is a button
on the Home tab to choose this format.
•
Currency. If you enter a number with a currency symbol (£ in the UK)
before it, the currency format will automatically be applied. There is
also a button in the Home tab to apply it.
•
Percentage. If you enter a number followed by a % sign, the
percentage format will be applied. There is also a button in the
Home tab to apply it.
•
Date. If you enter a number in a date format (such as 7/5/10 or
7-May-10), the date format will be applied.
Figure 27.30 shows the same number (1234) formatted in different ways
using the standard Home tab buttons. Note that the percentage format
button multiplies a number by 100, so if you want, for example, 50% to
be displayed, then you must enter 0.5.
Figure 27.30: The number formats
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Date format is automatically set in a cell if you enter something that
Excel® recognises as a date, such as 5/2/06 or 5-Feb-06.
Deleting data
If you delete the contents of a cell or cells that have been formatted (by
selecting the cells with the current cell pointer and pressing Delete), you
will delete what is in the cell but you will not remove the formatting. This
can have some confusing results. For example, if you enter a date in a
cell, the cell will automatically be formatted as a date. If you then delete
the date but at some time later enter a simple number in the same
cell, the number will be displayed as a date. If this happens, you can
change the formatting using one of the format buttons in the toolbar.
Alternatively, when you delete the date initially, use the Clear icon (a
pencil eraser) on the Home tab and choose Clear all from the dropdown menu; this will remove both the contents and the formatting.
Increase and Decrease decimal
Also shown in Figure 27.30 are the Increase decimal and Decrease
decimal buttons (next to the number format buttons). These allow you
to control the number of digits displayed after the decimal point.
Activity: Experimenting with
number formats
You can set many other number formats, as well as different versions
of the formats already described.
•
On the Home tab, click the menu launcher button at the bottom
right of the Number section. This brings the Format cells dialog
box on to the screen.
•
The Number tab allows you to choose the different formats for
numbers. Have a look at this dialog box and experiment with
the different formats. If there are any that you don’t understand,
or that you want more information about, search under help for
‘number formats’.
•
If you want a real challenge, consider a mythical currency called
the ‘Zap’. This has a rather strange format: the currency symbol
is a capital Z and it has three digits after the decimal point (there
are 1000 pennies in a Zap). The pennies are always preceded by
a letter p, so 25 Zap and 75 pennies would be written Z25.p075.
Create a custom number format for the Zap currency.
Formatting cells
Excel® has a full range of facilities to control the way information is
displayed, including being able to modify the font, size, attributes
(bold, italics, underline) and alignment (within the cell). As with the
number formats, you can set many of these using the icons in the Home
tab, but you can find the full range of options by clicking the menu
button on the bottom right of each section.
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Unit 27 Spreadsheet modelling
Some of the formats are worth mentioning in more detail:
•
Colours. You can set both the background colour of the cell and the
colour of its contents. The background colour button in the Font
section of the Home tab is a drop-down button called Fill Color.
When you click on it, it displays a choice of different colours.
•
Borders. It’s often useful to add borders to your spreadsheet, to
highlight important information such as totals and to separate
data into different sections. The Borders button is also a dropdown button. It displays diagrams showing how the borders will be
applied to the currently selected cell or cells.
•
Alignment. By default, numbers are aligned to the right of a cell
and text to the left, but you can change this alignment using the
buttons in the toolbar. If you click the menu launcher button at
the bottom of the Alignment section of the Home tab (see Figure
27.31) you will find some useful additional options you can set.
Figure 27.31: The Alignment tab of the Format Cells dialog box
You can set the vertical alignment in rows for text to be displayed at the
top, bottom or centre. You can also set the orientation of text so that you
can, for example, have text rotated through 90 degrees (i.e. on its side).
The Text control check boxes allow you to set the following options:
•
Wrap text. Text wraps within the cell (as it does in a text box).
•
Shrink to fit. The font size is automatically reduced so that text fits
in the cell. Without this option, when there is too much text to fit in
the cell, it will overflow across other cells.
•
Merge cells. This allows several cells to be merged so that they are
treated as one cell. This option can be useful if you want to enter a
lot of text, especially if combined with Text Wrap.
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There is a wide range of formatting options available. Make sure that
you use these options to improve the readability and appearance of
your spreadsheets. However, don’t overuse them or your spreadsheets
will look garish and unprofessional. Also, make sure you use formatting
in a consistent way, otherwise your spreadsheets will look messy.
Formatting sheets
Unlike a word-processing program, Excel® does not display the
spreadsheet as it will look when printed. You need to check this and, if
necessary, adjust various settings, such as the position of page breaks
and the page orientation.
To check the way the spreadsheet will look when printed, click the
Page Layout button in the View tab on the Ribbon. You will then see a
display similar to Figure 27.32.
Figure 27.32: Page Layout view
Page settings
On a spreadsheet larger than a single page of paper, you can use the
Page Setup dialog box to make sure that there are no page breaks in
awkward places. There are several ways of doing this:
•
adjust the margins so that the spreadsheet fits on a single sheet of
paper
•
adjust the page orientation to portrait or landscape
•
scale the spreadsheet so it fits on one page
•
adjust the position of the page breaks.
You can display the Page Setup dialog box by clicking the menu button
at the bottom right of the Page Setup section of the Page Layout tab.
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Unit 27 Spreadsheet modelling
Adjust the margins
If the spreadsheet is slightly larger than one page, but not much bigger
than that, you can adjust the margins so that it fits onto one page. Click
the Margins button on the Page Layout tab of the Ribbon. This will
display a series of pre-set margin options. Alternatively, you can click
Custom Margins at the bottom of the menu to display the Margins tab
of the Page Setup dialog box, shown in Figure 27.33.
Figure 27.33: The Page Setup dialog box
Adjust the page orientation
In some cases, adjusting the page orientation will enable a spreadsheet
to fit on a single sheet. You will need to adjust the page orientation in
any case to suit the layout of the spreadsheet. For example, if it has
more columns than rows, it will print better in landscape.
Select the Page tab of the Page Setup dialog box and then set the
orientation.
Scale the spreadsheet
Scaling the spreadsheet means making it smaller or larger so it fits on a
single sheet of paper. This only works if the spreadsheet is only slightly
larger than one page, otherwise the text can get too small. On the Page
tab of the Page Setup dialog box, you can choose to scale to a fixed
percentage or to fit on a certain number of pages (Excel® works out the
percentage scaling for you).
Adjust the position of the page breaks
You can move the page breaks so they occur in more convenient
places (e.g. not right in the middle of a set of data). The Page Layout
view allows you to see where the page breaks fall in your document.
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(Remember that you can swap between Page Layout and Normal view
using the icons on the Page Layout tab of the Ribbon.) By clicking the
Page Break Preview icon (next to the Page Layout icon), you can drag
them to the positions you want with your mouse.
If you drag the page breaks to the right or down, more information will
have to fit on a page, and the spreadsheet will automatically scale the
information to allow this. (See Figure 27.34.)
Figure 27.34: Page break preview
Header and footer
You can use the Header/Footer tab of the Page Setup dialog box to
choose from a selection of preset header and footer entries or you can
enter your own custom information. There are various buttons that allow
you to add page numbers and dates, etc., and format them, as shown in
Figure 27.35.
Figure 27.35: The Header/Footer
dialog box
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Unit 27 Spreadsheet modelling
Sheet
The Sheet tab of the Page Setup dialog box offers several options for
printing:
•
Gridlines – the lines separating rows and columns will appear in
print.
•
Row and column headings – the numbers of the rows and letters
of the columns will appear in print
•
Page order – you can select the order in which the pages of data
will be printed, as indicated by the pictures within the dialog box.
If you don’t want to print the whole spreadsheet, you can set a print
area. First select the area of the spreadsheet you want to print then click
the Print Area icon in the Page Layout section of the Page Layout tab
in the Ribbon.
Assessment activity
27.2
P3 P4 P5 D1
The university where you work as a trainee IT support specialist
has asked you to produce an automated class register using a
spreadsheet. It should be formatted in a similar way to a paperbased class register, with learner names down the side and the
date of each class across the top. P3 , P4
In addition to the things you would normally expect to find on
a paper-based register, the spreadsheet version should display
percentage attendance rates for each learner as the lessons
progress. The spreadsheet should also display a warning if any
learner’s attendance falls below 80 per cent. P5
Once you have completed the spreadsheet, write an evaluation of
it suggesting further improvements that could be made. D1
Grading tips
PLTS
Producing the register spreadsheet
will provide evidence that you are an
independent enquirer and a creative
thinker.
The evaluation you write for D1 will
provide evidence that you are a
reflective learner.
Functional skills
The spreadsheet you produce may
provide evidence for your Functional
Maths skills.
•To achieve D1 you will have to consider how well your
register spreadsheet meets the user’s need. You might find
it helpful to show it to a tutor and ask them how well they
think it would work as a class register, what’s good about
it and what could be better. Remember that when you
suggest further improvements you don’t actually have to
do the improvements, but you should explain how they will
make the spreadsheet better.
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2.10 Analysing and interpreting
data
Excel® includes some tools to help you analyse and interpret the data
in a spreadsheet. These tools can be particularly helpful when making
sense of large amounts of data.
Charts and graphs
One of the best ways to present data in an accessible format is to display
it as a graph or chart. Creating charts in Excel® is quite easy, although
you need to be careful to make sure that the correct data is included.
How to... Create a chart using the chart
wizard
To create a chart you use the Charts section on the Insert tab of the
Ribbon. The chart buttons work best with blocks of data that have
titles along the top and down the left-hand side. Figure 27.36 shows an
example of this layout. Before you click the Chart icon you should select
all the data including the titles then click the type of chart you want (in
this case a column chart) and the subtype (2D column shown below).
Figure 27.36: Creating a chart
Selecting an appropriate type of chart
The type of chart you need to choose partly depends on the data you have.
36
•
Line and area charts have data points that are joined up, so should
be used for data that represents a continuous change, such as
temperature over time.
•
Column or bar charts are better for financial data, such as the data
in Figure 27.36.
Unit 27 Spreadsheet modelling
•
Pie charts are good at representing proportions, such as the
percentage of people who voted for each party at an election. A
single pie chart cannot show multiple sets of data, as appears in
Figure 27.36. (We would need separate charts for North, South, East
and West regions.)
•
Choice of 2D or 3D is really personal preference, but 3D charts can
be hard to read accurately.
It may be that the standard chart Excel® produces is not quite what you
want. In that case, you can modify most aspects of the chart. You can also
resize your chart by dragging on the handles at the sides of the chart. Be
aware that if your chart is too small, the titles may not display properly.
Key terms
x-axis – the scale or items that run along
the bottom of the chart.
y-axis – the scale that runs up the side of
the chart.
How to… Modify a chart
Once you have created a chart, or selected an existing
one, the Chart Tools set of tabs will be added to the
Ribbon. In the Design tab you can do a number of things
such as:
•
change the chart type
•
change the title of the chart or the labels for the x
and y axis
•
change the colour scheme of the chart (the Chart
Styles section provides a scrolling list of many
different colours and effects).
to change. For example, you might want to change the
scale of the x-axis or y-axis of the chart. First click on the
axis to select it, then right click and choose Format Axis.
This will display the Format Axis dialog box, as shown in
Figure 27.37.
In the example shown in Figure 27.37, the minimum value
on the y-axis has been changed to 2000 and the major
units indicated on the axis have been set to an interval of
2000. You can see the result on the chart itself.
To select the data to use for the chart, the Select Data
icon in the Data section allows you to choose the cells
to include or exclude from your chart. This is useful if the
data has an empty row or column in it, or if you want to
leave out one of the rows or columns of data.
To choose a different chart layout, the Chart Layouts
section provides a scrolling list of different layouts. For
example, the standard chart does not have a title but you
can choose a layout with a title from this list. This will insert
the text Chart Title in your chart, but you can click in this
and type your own title. Some of the chart layouts let you
add titles to the axis as well.
As well as using the Chart tools to modify your chart, you
can also click on the part of the actual chart you want
Figure 27.37: The Format Axis
dialog box
Filtering and sorting lists
Dealing with lists and simple databases is one of the many strengths of
Excel®. People often use Excel® to keep track of lists, rather than using
a database product such as Microsoft® Access®, because it is easier to
understand and set up. In fact, all you really need to do to set up a list
in Excel® is add field titles at the top.
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BTEC’s own resources
Figure 27.38 shows a version of the Games Store spreadsheet we used
before. We will use it to look at how lists can be filtered and sorted. Every
column of data has a title (or ‘fieldname’ in database terminology). Columns
for the types of game and the hardware platform have been added.
Figure 27.38: The Games Store games list
How to… Sort lists
There are various reasons why people want to sorts list – to find the
cheapest, the newest, the best selling and so on. To sort a list, all you
need to do is make sure
the current cell pointer
is somewhere in the
column you want to sort,
then, from the Home
tab click Sort and Filter
and chose AZ or ZA
(this works with both
alphabetic and numeric
data). Excel® will then
sort the whole table
of data. Figure 27.39
shows the games sorted
in ascending order by
price (cheapest first).
Figure 27.39: Games sorted by price
Filtering is more sophisticated than sorting, as it lets you pick out a
record or records in the list that match certain criteria.
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Unit 27 Spreadsheet modelling
How to… Filter data
box in the Platform column now has a little filter
icon in it, indicating that the field has a filter applied.
As long as you have field titles in the first row of your list,
you can use the data filter.
•
Make sure the cell pointer is somewhere in the list
of data and then choose Filter from the Sort and
Filter drop-down menu. This will display a little
drop-down arrow beside each of the fieldnames in
the top row of the list, as shown in Figure 27.40.
•
If you only want to display the Xbox games, click on
the arrow next to the Platform title and remove the
tick next to PS3 in the Text Filter area at the bottom
of the menu, so only Xbox has the tick next to it (see
Figure 27.40).
•
Now click OK at the bottom of the menu and the
filter is applied (see Figure 27.41). The drop-down
•
To return to the display of all the data, click the Filter
icon again and the Select All option. Then click OK.
•
You can apply more sophisticated filters if you wish.
For example, you might want to list all the games
with a price of less than £30. To do this, click the
Filter icon next to the Price fieldname, then choose
the Numbers filters option and the Less than
option. The Custom Filter dialog box shown in
Figure 27.42 will appear.
•
Enter 30 in the box on the right (see Figure 27.42) and
click OK to apply the filter. Your list will now display
only games under £30, as shown in Figure 27.43.
Figure 27.42: Custom Filter dialog box
Figure 27.40: Filtering a list
Figure 27.41: A filter applied
Figure 27.43: Games under £30
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BTEC’s own resources
PLTS
Justifying the use of a chart will
demonstrate that you are a reflective
learner.
Analysing the attendance data
will demonstrate that you are an
independent enquirer.
Functional skills
Writing reports for these assessment
tasks will provide evidence for your
Functional English skills in writing.
Analysing large and complex
spreadsheets
When you are trying to analyse data from large and complex
spreadsheets, you may make more sense of the figures if you restrict
your analysis to just the totals or subtotals. Although sorting and
drawing charts make interpreting data easier, if there is a very large
amount of data in the first place, then the resulting chart, sort or search
may not make much sense.
For example, if you draw a bar chart from a very large amount of data,
then the resulting chart will have so many bars it will be difficult to read.
In this situation it may be better to create subtotals based on a date or
month range and then graph this data. The resulting chart will be much
smaller and, therefore, easier to read and interpret.
Just checking
1. If a cell contains the number 10, and you use the percentage format button in the toolbar to format
the cell, what will be displayed?
2. Your spreadsheet is slightly larger than a single sheet of paper. How can you make it print on just
one sheet?
3. How can you select non-adjacent cells (i.e. cells that are not all together in one block)?
4. What must you do before you use the Filter menu option?
5. Where is the x-axis on a graph – along the bottom or up the side?
Assessment activity 27.3
You have been asked to further refine the register
spreadsheet you produced earlier.
1.Add some example data to your spreadsheet and
create appropriate charts showing the learners’
attendance percentage figures and the total class
attendance each week over the weeks of the
course. P6
2.Write a justification for using a chart to present the
learner attendance figures and for the type of chart
you chose. M2
3.The spreadsheet currently displays a warning if a
learner’s attendance falls below 80 per cent. Add
a facility to your spreadsheet so that the user can
change this percentage. Test your spreadsheet with
different percentages and check that the warning
messages work correctly. M1
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P6 M1 M2 M3
4.Write a report for the Head of Department
analysing the attendance data, identifying
overall trends for the whole class and for
individual learners. M3
Grading tips
• It may be best to ask your tutor to provide
some real attendance data for question 4. Just
using random data will not make analysis easy.
•When writing your report for question 4, you
might comment that over the weeks of the
course the overall attendance has improved.
For individual learners their overall attendance
might have improved or got worse over the
course, or there may have been several weeks
when they did not attend due to illness. Include
the chart you have created in the report.
Unit 27 Spreadsheet modelling
3. Be able to test and document
spreadsheet models
3.1 Test
It’s very easy to assume that, because a computer is doing the
calculations, they must be correct. However, the computer only does
what you tell it to do, so you must be careful that the formulae you enter
are correct. If not, the calculations will be done correctly but they will
be the wrong calculations! To make sure your formulae are correct, you
need to check them manually with a calculator. Where your spreadsheet
contains automations such as macros or links to other spreadsheets you
will need to check these work correctly. You should also check that the
formatting and layout of the spreadsheet is neat and consistent.
As well as checking that your spreadsheet works correctly, you also need
to check that it meets the requirements of the users you produced it
for. You can do this by revisiting the design document you originally
produced, which defines what the spreadsheet should do. Check to
make sure your spreadsheet does what you said it would do and you
haven’t forgotten anything.
3.2 Documentation
Documentation is an important part of any solution. Producing a
working solution without documentation will lead to problems later.
The user guide you produce should provide all the required information
that your users will need to make use of the spreadsheet model. You
should already be aware of how the users will want to use what you have
produced, and your documentation should guide them step-by-step
through that process. You will need to add a troubleshooting section
to your documentation which explains how to deal with common
problems.
As part of developing your documentation, you might find it useful to
show your spreadsheet model to someone who has not seen it before.
Ask them to try to use it following your step-by-step instructions. See
what problems they have and what questions they come up with.
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BTEC’s own resources
Functional skills
Producing user documentation for
your spreadsheet will provide evidence
for your Functional English skills in
writing.
Assessment activity
27.4
P7 P8 D2
1.Create another worksheet in your class register spreadsheet
which contains the register for another class. Add some
example data for this register. Then create a third worksheet
in your class register which will be used as a management
summary of the attendance data from the other two sheets.
The management summary sheet should only show the overall
learner attendance percentages, not the attendance figures for
each class. D2
2.To make a new register for a class it is necessary to copy
a blank register (with no attendance data in it) to a new
worksheet. Record a macro for your class register spreadsheet
which will do this task for you. D2
3.Test your class register to ensure it works correctly and
calculates learner attendance percentages correctly. P7
4.Produce user documentation for your register spreadsheet
which explains how to use it. P8 .
Grading tips
As you are a learner, you will probably not have real end
users for your class register. But you should consider asking
your tutor or fellow learners to review what you have done
and compare it to your design. Doing this will help you to
ensure that your work meets the pass grade requirements
(‘test a spreadsheet to ensure that it is fit for purpose’). It
may also provide some evidence for a distinction (‘evaluate a
spreadsheet model suggesting further refinements’).
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Simon Osoba
Unit 27 Spreadsheet modelling
BTEC’s own resources
Junior Technician in an IT support department
I use spreadsheets
frequently in my work. Most of the time I
just use them to manage lists of data. For example,
I keep a spreadsheet of all the computers we have and
the software that is installed on them so we can check
licensing.
When we buy new equipment we often create a spreadsheet
to compare different options. We put all the different prices
in and then play around with the quantities, suppliers and
things like cheaper or more expensive items, to see how
this changes the total cost.
I have recently been working on a user
satisfaction survey. We do this every year to check how good a
job the users think we are doing. I was asked to create a spreadsheet that
we could put all the results in and analyse them. The IT director wanted charts
showing the results for every question on the survey. I also had to link this year’s
spreadsheet with the results from last year, so she could compare the two and see
where we are getting better and where we are getting worse.
I quite enjoy using spreadsheets – there is so much they can do and there is
always something new to learn.
Think about it!
1. What spreadsheet skills will Simon need to use to produce
the spreadsheet he mentions above?
2. What could spreadsheet models be used for in your school
or college? Think of four or five different uses.
3. What about in business? Think about how spreadsheets
could be used in a small company such as a shop.
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BTEC’s own resources
Just checking
1. What are the different sorts of ways in which a spreadsheet can be used?
2. What are the formats in which you can save a spreadsheet? Why might you want to use these
different formats?
3. Explain the difference between relative cell referencing and absolute cell referencing
4. List four useful spreadsheet functions and explain what they do.
5. Explain how ‘AND’ and ‘OR’ logical operators can be used in an ‘If’ function.
6. Explain what a macro is and how you can create one.
7. What are the main data types you can use to format numbers in a spreadsheet?
8. What are the main types of chart you can use and what sort of data is each type best at displaying?
9. Why is it important to test a spreadsheet?
Assignment tips
• This unit links with Unit 9: Customising software. Both units require you to produce a macro, so you can
cover both requirements with the macro you create in this unit.
• Remember that this unit is not just about spreadsheets – it is also about spreadsheet models, so the
spreadsheet you develop for assessment must have an aspect of modelling to it. Your spreadsheet needs
to have rules (based on formulae) which can be changed so you can see the effects.
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