Download Engineering Statistics Excel Tutorial

Engineering Statistics
Excel Tutorial
Page 1
The three Excel assignments in this Lab should adhere to the following format:
A. Your name should appear left justified at the top of each page of each spreadsheet. Immediately
below your name the Assignment number must appear in the form "Assignment _ ". The date of
the assignment's completion should appear at the top right of each page of the spreadsheet. To
access Headers use the command sequence Insert Header & Footer.
B. All the assignments of this Lab should be handed in at the same time, stapled to the first page.
Do not hand in the assignments piece meal. Wait until all three assignments have been
completed.
I. Introduction
A spreadsheet program like MS Excel allows you to enter numbers and labels into cells which make a
two-dimensional array or table called a spreadsheet. The rows of the spreadsheet are labeled by numbers
and the columns by numbers. In addition to storing information, a spreadsheet's real power comes from
performing calculations and generating graphs. Furthermore, if the contents of a given cell are changed,
this change is automatically incorporated into the calculations or graphs. For this reason, calculations in
a spreadsheet should always be stated as formulas involving the addresses of the cells containing the
data rather than the numerical values of the data. This illustrated below.
Cells D2-D4 contain the values 9, 8, and 6 respectively. To place the sum of this column (23) in cell D5,
we type the equal sign in the command line. This tells Excel that we are entering a formula. The
"function" name we want is sum. Selecting "SUM" from the functions bar results in the dialogue box
shown below. We need to indicate that the block of cells to sum is D2-D4. One way to do this is to click
on the "little spreadsheet" icon shown in the extreme right of the Number 1 data box. This returns you
to the spreadsheet and allows you to select with the mouse those cells which are to be summed. Once the
selection has been made press the enter key. Then click on "OK" in the dialogue box.
Al Lehnen
Madison Area Technical College
12/17/2010
Engineering Statistics
Excel Tutorial
Page 2
A second alternative is to simply type "sum(d2:d4)" in the command line and then press the enter key.
A third alternative is to place the cursor in the cell D5 and left click on the sigma (summation) button
and press the enter key..
Al Lehnen
Madison Area Technical College
12/17/2010
Engineering Statistics
Excel Tutorial
Page 3
In any case what is shown in cell D5 is the computed sum. (To actually see the formula in a cell rather
than the result of its evaluation use the command sequence click on Formulas Show Formulas.)
Another feature that makes spreadsheets easy to use is the use of relative addressing in copying and
pasting. Suppose we have two columns x and y, with x in cells B4-B9 and y in cells C4-C9. We want to
make a new column z, where each entry in the z column is the sum of the corresponding entry in the x
column with twice the corresponding entry in the y column. Stated as a formula z = x + 2y . To put this
formula into spreadsheet language, we compute the first entry in the z column, D4 as +B4+2*C4. Using
the leading + sign lets Excel know that we are entering a formula without having to depress the = sign in
the command line.
We could enter the corresponding formulas for cells D5-D9, but this is rather tedious, especially if there
were a large number of cells. Here's where the magic of relative addressing comes in. We select cell D4
Al Lehnen
Madison Area Technical College
12/17/2010
Engineering Statistics
Excel Tutorial
Page 4
and copy its contents into the clipboard. Then we select the cells D5 –D9 and right click with the mouse
to get the selection menu. We choose to paste the clipboard into the selected cells. You might think that
this would paste +B4+2*C4 into each cell. In fact, we get just what we wanted. Excel is "smart enough"
to know that the C column is being added to twice the D column, so it changes the cell addresses for
each cell. This is what relative addressing is all about.
Sometimes we don't want to copy and paste cell address "relatively". For example, if a formula must
always use the contents of cell G17 regardless of what cell contains the formula, we would refer to cell
G17 in the formula as $G$17 . The use of the $ means that if this formula is copied and pasted into
another cell, the contents of cell G17 will still be used in the computation. The use of the $ with cell
addresses is called absolute addressing.
Excel Assignment 1:
Go to the website http://faculty.madisoncollege.edu/alehnen/TechmathII/TechMathIILabs.html and
download a copy (“right click” on the link and choose “Save Target As”) of the Excel file Salesort.xls.
In Excel open this file. Using formulas and the Format/Format Cells menu modify the worksheet so
that it appears as follows:
A. All column widths are adjusted so that all column headings fit.
B. All columns except "Sales Associate" and "Employee Code" are displayed as currency with 2
decimal digits.
C. The "First Quarter Sales" Column is the sum of each associate's sales from January through March.
D. The "Commission" Column is 6.5% of the First Quarter Sales Column.
Al Lehnen
Madison Area Technical College
12/17/2010
Engineering Statistics
Excel Tutorial
Page 5
E. All Column headings are bold and a blank row separates the column headings from the sales data. A
single width line underlines the row of Column headings.
F. In addition to the original order of associates, three other listings of the spreadsheet results are to be
shown, each separated by a blank row. So make three copies by using select, copy, and paste. The first
listing should have the associates' names in alphabetical order. The second listing should be in ascending
order of the Employee Code, while the last listing should be in descending order according to First
Quarter Sales. To sort a block of cells, select Sort from the Data menu. Since all four listings are to be
displayed in the final form of the spreadsheet, be sure to make a copy of the rows before executing the
sort. That is, first make the changes to the rows in the order given, then make a copy of these rows
below them, then sort the copied rows. Repeat this process until all four listings are in the same
spreadsheet.
G. Insert a three-D pie chart showing the contribution of each associate to first quarter sales. Select
Data Choose Add a Series and select the first quarter sales. Select the column of names of sales
associates as the Category (X) axis labels. This graph should have a title of First Quarter Sales. Right
click on the pie chart and select Add Data Labels followed by Format data Labels and add the
Category Name (Sales associate’s name) on each slice of the pie. Once the chart appears right clicking
on it (or any portion of it such as titles or labels) brings up an "object menu" which allows you to make
changes. The chart can be resized in the same way as graphic images in MS Word. Insert the chart into
your spreadsheet.
H. Print the spreadsheet. Use Print Preview and its Page Setup option to get a printout that is easy to
read and understand. Use the Scaling adjust option under the Page index label of the Page Setup menu
to insure that all columns printed fit on one page.
Excel Assignment 2:
Go to the website http://www.weather.gov/climate/index.php?wfo=mkx of the National Weather Service
Forecast Office. Choose the following options: 1. Product: Preliminary Monthly Climate Data (CF6),
2. Location: Madison, 3. Timeframe marked: Archived Data to find the maximum, minimum, and
average temperatures recorded in Madison for each day of the preceding calendar month. In an Excel
spreadsheet enter this temperature data in four columns. The first column is Day and runs from 1 (the
first of the month) to the last day of the month. Compute the average, median and sample standard
deviation (using the Excel functions AVERAGE, MEDIAN and STDEV) for the Maximum,
Minimum, and Average columns and format these results to two decimal places.
Al Lehnen
Madison Area Technical College
12/17/2010
Engineering Statistics
Excel Tutorial
Page 6
Next create a Scatter chart that shows the Maximum, Minimum, and Average versus Day all on one
graph. Insert a scatter plot that displays just the data points as shown below.
Click on the chart and select data. Enter a new series with the x axis the day of the month and y the daily
high temperature. Repeat this procedure for the daily low temperature and the daily average temperature.
Al Lehnen
Madison Area Technical College
12/17/2010
Engineering Statistics
Excel Tutorial
Page 7
Click on a data point to Format Data Series which allows you to change data marker size (Marker
Options) and connect points with line segments (Line Color, Line Style).
Al Lehnen
Madison Area Technical College
12/17/2010
Engineering Statistics
Excel Tutorial
Page 8
Clicking on the chart and selecting Format Chart Area allows you to insert borders and modify the graph
window. Double clicking on the chart brings up the chart layout menu which allows you to add titles to
the chart and axes. Clicking on the x axis gives options such as adding grid lines. The “finished” product
is shown below. Generate a “similar” graph for your spreadsheet.
+
Al Lehnen
Madison Area Technical College
12/17/2010
Engineering Statistics
Excel Tutorial
Page 9
II. Generating Linear Models in Excel
Given a set of X, Y values where Y is the dependent variable and X is the independent variable, the
"best" straight line through the data can be determined by the method of "least squares". This linear
modeling of the relationship between X and Y is calculated by the equation Y = m*X+b , where m is the
slope of the line and b is the y intercept. In Excel this least squares or "regression" slope can be
calculated with the SLOPE( ) function. The SLOPE function's input menu requires the cell addresses of
the Known_y's and the Known_x's. These may be entered directly, or if you click on the "little
spreadsheet" icon you will return to the spreadsheet where you can select the appropriate cells. After
selecting the correct input, click on the OK button to calculate the slope. The regression y intercept is
calculated in a similar fashion with the INTERCEPT( ) function.
To calculate the estimated Y values based on the linear model copy and paste the formula Y=m*X+b as
shown below. Note: the use of absolute addressing for the cells containing the slope and y intercept.
Al Lehnen
Madison Area Technical College
12/17/2010
Engineering Statistics
Excel Tutorial
Page 10
Finally, a 2-D XY (Scatter) plot of the data plus the linear model can be constructed as shown below.
The chart sub-type chosen was Scatter with no connecting lines or curves between data points. Then the
series option was used to plot both the (X, Y) data pairs and the (X, Y Estimate) pairs. Right click on a
Y Estimate point and select Format Data Series and connect the estimated y data points connected by a
thin continuous line. You can control how you want the graph to look by “clicking” on its various
elements. The result of these modifications is shown below.
Excel Assignment 3:
Al Lehnen
Madison Area Technical College
12/17/2010
Engineering Statistics
Excel Tutorial
Page 11
Below is data giving the yearly energy consumption in millions of BTU's and the area in thousands of
square feet of building shell for 22 warehouses all subject to the same climatic conditions.
Shell Area (Kft2)
MBTU/Year
Shell Area (Kft2)
MBTU/Year
30.00
3,870
23.68
2,680
13.53
1,371
5.65
337
26.06
2,422
8.00
568
6.36
672
6.15
555
4.58
233
2.66
239
24.68
219
19.24
2,629
2.62
354
10.70
1,102
23.35
3,135
9.13
424
18.77
1,470
6.51
545
12.22
1,408
13.53
1,691
25.49
2,201
18.86
1,870
A. Enter the data as two columns in an Excel spreadsheet. Consider the column of Shell Areas to be X
and the Energy Consumption to be Y. In the cell beneath each column calculate the average value of
each variable in fixed digit format with 1 decimal place. Calculate the regression slope and regression y
intercept for this data.
B. Create a third column by applying the linear model. That is, for each value of shell area calculate
what the linear model predicts for the energy consumption. In the cell beneath this column calculate the
average of the predicted energy consumption in fixed digit format with 1 decimal place.
C. Generate a 2-D XY (Scatter) graph of Energy Consumption versus Shell Area. Give the graph an
appropriate title and label the axes. Plot the predicted linear energy consumption on the same graph as
the actual energy consumption. For this Series add line segments between the plotted points.
D. Insert your graph in the spreadsheet and print out the results.
Al Lehnen
Madison Area Technical College
12/17/2010
Engineering Statistics
Excel Tutorial
Page 12
E. In MS Word write answers to the following questions, print the document and attach this to printed
spreadsheet.
How does the average predicted energy consumption compare to the average actual energy
consumption?
How well does the linear model fit the data?
What data point deviates the most from the linear model?
Estimate the yearly energy consumption of a building whose shell area is 17,500 square feet. Explain
how you obtained this estimate.
Al Lehnen
Madison Area Technical College
12/17/2010