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ENG 1181
Microsoft Excel: Data Analysis
Trendlines
Formulas
Functions
Cell Addressing
College of Engineering
Engineering Education Innovation Center
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ENG 1181
Review - Data Analysis with Excel
Excel offers many capabilities for analyzing data:
1. Trendlines for predicting data values
2. Use of equations to do sophisticated calculations with
the worksheet data using cell referencing
3. Comprehensive library of built-in functions to help
calculate and analyze spreadsheet data
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ENG 1181
Review - Cell Reference: Relative Addressing
• Relative Cell Address – refer to the cell in the same
relative position
• Ex: B12 – relative reference to value in cell B12, use fill
handle to drag to cell C17
Step 1
Step 2
Step 3
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ENG 1181
Review - Cell Reference: Absolute Addressing
• Absolute Cell Address – always refer to the same cell
• Ex: $B$12 – absolute reference to value in cell B12, use
fill handle to drag to cell C17
Step 1
Step 2
Step 3
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ENG 1181
Review - Formulas and the Excel
Function Library
• Formulas are used to calculate values in a cell in a
worksheet based on values stored in other cells with
optional use of the Excel function library.
• There are hundreds of functions available
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ENG 1181
Review – Examples of Functions in Excel
• Trigonometric functions
• COS(cell) – calculates cosine of an angle
• PI() – calculates pi
• Mathematical functions
• EXP(cell) – raises e to the power “cell”
• SQRT(cell) – finds the square root of cell
• Statistical functions
• AVERAGE(cells) – finds the mean of a list of cells
• STDEV(cells) – finds the standard deviation of a list of cells
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ENG 1181
Predicting Data - Trendlines
• Excel graphing allows you to graph data and then create
an equation that best fits that data.
• You can choose the type of equation for Excel to use,
such as linear, exponential, logarithmic, etc.
• With a best-fit equation you can predict data values not
included in the worksheet
• Note: You must use X-Y Scatter Plots
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ENG 1181
Example – Predicting Values
Year
Births
Deaths
2002
3,167,788
1,909,440
2003
3,612,258
1,989,841
2004
3,680,537
1,974,797
2005
3,669,141
2,039,369
2006
3,756,547
2,105,361
2007
3,909,510
2,167,999
2008
4,158,212
2,148,463
2009
4,110,907
2,169,518
2010
4,065,014
2,175,613
2011
4,000,240
2,268,553
2012
3,952,767
2,278,994
Question:
How many births
and deaths would
we expect in
2016?
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ENG 1181
Scatter Plot of Example Data
US Population Statistics
4,500,000
4,000,000
3,500,000
3,000,000
2,500,000
Population
Births
2,000,000
Deaths
1,500,000
1,000,000
500,000
0
2000
2002
2004
2006
2008
Year
2010
2012
2014
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Adding a Linear Trendline
1. Right click on any data point
and select Add Trendline.
2. Select Linear as the
regression type
*Note that there are other options
available to you
3. Select Display Equation on
Chart
ENG 1181
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ENG 1181
Trendline for Births
Note: You may
need to re-format
the trendline
equation to
improve resolution,
or move the
equation for
readability
US Population Statistics
4,500,000
y = 71959x - 1E+08
4,000,000
3,500,000
3,000,000
Population
2,500,000
2,000,000
Births
1,500,000
Deaths
1,000,000
500,000
0
2000
2002
2004
2006
2008
Year
2010
2012
2014
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Formatting Trendline Label
1. Click on
trendline label
2. Right-click on
edge of label
box
3. Select Format
Trendline Label
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Formatting Trendline Label
4. Select Number
5. Set Decimal
Places to 0
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ENG 1181
Results
US Population Statistics
Using these equations,
we can predict the
numbers of births and
deaths expecting in 2016:
4,500,000
y = 71,959x - 140,595,281
4,000,000
3,500,000
3,000,000
Births : 4,474,063
Deaths: 2,428,399
Do you see any problem
with these predictions?
y = 35,168x - 68,470,289
2,500,000
Population
Births
2,000,000
Deaths
1,500,000
1,000,000
500,000
0
2000
2002
2004
2006
2008
Year
2010
2012
2014
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ENG 1181
Example – Subtracting Data
How do we find the
difference between
births and deaths for
each year in the
table?
1. Select cell E4
2. Type: = c4 – d4
3. Press enter
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ENG 1181
Example – Subtracting Data
Note cell E4 now displays
the difference between cells
C4 and D4.
Also, note the formula bar
shows you the actual
calculation in cell E4. The
formula bar always shows
the actual contents or
formula of the selected cell.
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ENG 1181
Copying Formulas
1. Select cell E4, where
equation resides
2. Move cursor to lower
right corner of E4, until
it changes to a small +
(fill handle)
3. Left click and drag
down to cell E14
4. The formula is copied
from E4 through E14
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ENG 1181
Copying Formulas
Note how Excel uses relative
cell addressing when copying.
Select cell E14, then look in
the formula bar. What does it
tell you?
Cell E14 should contain:
=C14-D14
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ENG 1181
Formulas & Excel Function Library
• Excel allows for the use of sophisticated equations and
functions to be used
• Operations
– Multiplication: *
– Division: /
– Exponents: ^
• Note that ‘e’ is not defined
– Instead, use: exp( )
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ENG 1181
Order of Precedence
• Higher-precedence operations are executed before
lower-precedence operations
• If two operations have the same precedence, then the
expression is executed from left to right.
• Excel’s Order of Precedence is:
1. Parentheses (innermost pair first)
2. Exponentiation
3. Multiplication and Division
4. Addition and Subtraction
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ENG 1181
In-Class Exercise:
Type the following expressions in Excel. Share your answer with your
teammates. Discuss the order which the operators are executed.
Expression:
Answer:
1. = 7 + 8 / 2
1. Result = 11 ; 8 / 2 executed 1st
2. = (7 + 8) / 2
2. Result = 7.5 ; 7 + 8 executed 1st
3. = 27 ^ 1 / 3 + 32 ^ 0.2
3. Result = 11 ; 27^1 and 32^0.2 executed 1st ,
then / , then +
4. = 27 ^ (1 / 3) + 32 ^ 0.2 4. Result = 5 ; 1 / 3 executed 1st , then ^, then +
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ENG 1181
Formulas & Excel Function Library
• Equations can be combinations of the mathematical
operators and functions.
• The Excel functions can be accessed in two ways:
– select the Formulas tab on the ribbon, or
– type the function name in the cell or formula bar
• Remember to use proper cell referencing (see
following example)
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Formula Example
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We want to get the following
function into Excel so we can
plot the data.
x(t) = 10 e(-0.5t) sin(3t +2)
We need to use Excel’s function
library to do this. Type in the
equation after select the tab
labeled "My Example :
=10*EXP(-0.5*B3)*SIN(3*B3+2)
Copy this formula through Cell
C23. Now you can view a plot
of the data!
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ENG 1181
Absolute Cell Addressing using Multiple
Sheets
At the bottom of the
worksheet, select the tab
labeled “Absolute
Addressing Example”.
This moves you to a
different sheet within the
workbook.
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ENG 1181
Absolute Cell Addressing Example
x(t) = 10 e(-0.5t) sin(At +2)
Change the value in
cell B2 to see
dynamic changes of
the graph. Reset cell
B2 to 1.
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ENG 1181
Absolute Cell Addressing Example
In Excel, you also have the ability
to reference cells located in a
different sheet.
My Example
1. Select the tab labeled ″My Example″. In
cell C3, select the 3 in the equation and
then hit the delete key
2. Select the tab labeled “Absolute
Addressing Example”
3. Select the cell B2
4. Press the ″Enter″ key
5. You have now returned to ″My Example″
Absolute Addressing Example
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ENG 1181
Absolute Cell Addressing Example
First hit the up-arrow key to reselect cell C3. Before you drag the
new formula in cell C3 of ″My Example″ to adjust the remaining
cells, make sure you add “$” to the equation so that the cell you
reference in ″Absolute Addressing Example″ tab is an absolute
cell reference.
After dragging cell C3 to C23 in ″My Example″ tab and change the value
of A in cell B2 of ″Absolute Addressing Example″ and return to ″My
Example″ to see dynamic changes of in that graph by changing cell B2.
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ENG 1181
Absolute Cell Addressing Example
To organize the various worksheets
within your workbook, it is helpful to
give them descriptive names.
1. Right click on ″My Example″ tab
2. Select “Rename”
3. Enter a name for the worksheet.
(Here we call it ″My Sinusoidal
Function″)
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ENG 1181
Homework Assignment
• See the assigned work on the appropriate
Class page on the EEIC website.