Communicating Quantitative
Information
Spreadsheet lesson: unit pricing
Graphs
(Exercise: coin flips)
Homework: Spreadsheet & graph assignment.
Continue postings.
News?
• Primary
– Do vote. New voting machines. You can make
posting on old versus new.
– Predictions on results?
– Results?
• ?
Unit pricing
• Prices for products are $/quantity
– cost/unit
• Generally, more costs more but….often
not that much more
• $1/bagel unit cost is $1/bagel
• $5/dozen bagels unit cost is ….
answer is
• .41666666
• round off to .42, 42 cents
• Okay to round off, but you need to know
you are doing it.
• Reasonability check: if it were $6/dozen,
the answer would be…..
• 6 dollars for 12
• 50 cents for 1
Excel basics
• Excel grid:
– columns use letters: A…Z, AA, AB…
– rows are numbered
• Cell can hold
– Text
– Number
– Formula: can refer to other cells
• Cell can be formatted
–
–
–
–
Number
Centering, justification
Color
Font, etc.
Cookie lab
•
•
•
•
Create columns for each type of cookie
Label (text) rows
Record number of cookies eaten
Use information on box to enter
– cost/box, cookies/box, calories/serving, etc.
• Use formulas to compute cost/cookie,
calorie/cookie
• Use formulas to compute YOUR cost and
calories
• Use formulas (sums) to compute total cost and
calories
Copy-and-paste
• Can copy any cell
• Copy-and-paste formula with cell
references modifies new references
– Relative addressing
Cookie lab
• For second, and subsequent cookies
– Use copy-and-paste for formulas
– NOT for data
– What values are formulas and what data
specific to each cookie?
Excel basics
• Built-in functions
– Sum
– Average
– others
• Watch out for default/automatic action. For
example, make sure range is what you
want.
=SUM(B2:D2)
Excel basics
• Changing cell(s) forces immediate re-calculation
of any formula using that cell.
• Inserting a new cell forces immediate recalculation of any formula using a range
including the new cell.
• Cookie lab:
– Try it: change number of cookies eaten. Add a
column for a new cookie
Cookie lab
• Add formatting
– Special conventions for money
– Note: data remains the same regardless of
what you see, so you can change
• Add taxrate
– Use either absolute addressing ($A20)
– Use named cell
• Add ????
Excel formatting
• Fonts
• Text size
• Column & Row size
– Hide columns and rows
• Decoration
– View/Toolbars/Drawing
• Color
Excel basics, cont.
• Copy and paste of cell formulas will adjust any
[regular] cell reference
=B10/B11 in column B will by changed to
=C10/C11 when copied and pasted to column C
• This is generally what you want.
• If not: use absolute references
=$B$10/B11 in column B will be changed to
=$B$10/C11 when copied and pasted to column C
Excel graphs
• Bar (comparable values)
• Line (time series, other dependencies)
• Pie (parts of a whole)
• Others
What graph makes sense?
When is a graph better than words or a table?
…. More data
Create Pie chart: parts of a whole
•
•
•
•
Select data (cells with calories, NOT total)
Click on graph icon
Select pie, accept first pie choice & click on Next
Click on Series, click in Category Labels box.
Select names of Cookies in main spreadsheet.
Enter. Next.
• Check off Category name, percentage boxes.
• Finish.
• May need to drag graph to position on
spreadsheet.
Create Line graph
• Select Data and click on graph icon.
• Choose Line, pick subcategory. Next.
• Click on series. For Category name: select
column labels (e.g., months).
• For each series (now called series 1,
series 2, etc.): click in Name box, Select
Row label. Enter.
• Next. Finish.
Spreadsheet
• “killer ap” for personal computers
• People could examine data
– Do ‘what if’ experiments
• Produce professional tables and graphs.
Distribution
• … record counts of each value reports
– individually or in ranges
• Excel: can generate distributions using
the frequency function. This requires
special keystrokes since it is an array
function.
• =frequency(data,bins)
Scores from class
• Assume final scores are in a2:a25
• High end of ranges (bins) are in c2:c10. Will
reference c11 because one more bin is inferred.
• Type into f2
=frequency(a2:a25,c2:c11)
Select f2 to f12
Press function key f2. Press CTL-SHIFT-ENTER
This produces the frequency counts.
Sorry about
coincidence!
Graph
• Write into G2 through G12 the grades
corresponding to these totals: F, D-, D, … up
through A.
• Select F2:F12 and click on Chart/Graph icon.
Choose bar graph (columns). Next. Enter in a
title. Click next and finish. May need to reposition chart. Right-click, choose source data.
Click on Category (x) axis labels. Select
G2:G12.
Frequency: array formula
• Scores  bins  histogram
• =frequency(data, range_upper_bounds)
– range_upper_bounds contains 1 more slot:
those scores > last number
• Need to use special keystrokes to enter as
array formula
– f2, shift-control-enter
Scores
45
67
86
81
76
71
90
50
60
70
80
90
F
D
CC
B
A
1
0
1
2
3
0
Grades
3.5
3
2.5
2
1.5
1
0.5
0
F
D
C-
C
B
A
Results from Fall class
Grades
8
7
6
5
4
3
2
1
0
F
D-
D
D+
C-
C
C+
B-
B
B+
A
Excel files
http://faculty.purchase.edu/jeanine.meyer
/quant/exampledistribution.xls
http://faculty.purchase.edu/jeanine.meyer
quant/simpledistribution.xls
Binomial Distribution
• Note: when flipping coins, any single sequence
of heads and tails is equally likely!
– HHHHHHHHHH
– HTHTHTHTHT
• There are more sequences with 5 heads and 5
tails than any other combination
– will return to this topic later. Extra credit to make a
posting explaining the formula.
• When flipping coins in a sequence (assuming a
fair coin), the odds of heads on the next flip is ½
no matter what the sequence has been.
Class Exercise
• Flip a coin 10 times. Record number of
heads.
– What are possible values?
• I will record data points and we will see the
distribution evolving…
Bar graph
• Select data. Click on graph icon. Choose
bar graph…
• Right click. Enter column/row with suitable
labels for Category (x) axis.
Homework
• Choose one of the following:
– Personal or Institution or Government budget
• Columns are months & Rows are expenses and income
• Include sums, net, averages
• Graphs: pie charts on expenses, stacked bar or line graph on
expenses and income.
– Sports record(s)
• Columns are years & Rows are name of record. Group so
unit of cell is common: times, distance, weights, etc.
– ? (Confirm with me)
Homework, continued.
• May work in pairs
– More expected from pairs than individuals.
• Prepare spreadsheet and graphs
• Decide on positive and negative aspects
of graphs for communicating your
situation.
• Keep up on postings.