For this homework assignment, please PRINT OUT your results and turn these in on Thursday, Oct 16.

Note: The TRACWAY.XLS file is quoted from Statistics, Data Analysis and Decision Modeling, by James R. Evans and David L. Olson, Prentice-Hall, 2000. I have added additional worksheets or commentary to some of the examples.

• Open the file TRACWAY.XLS and locate the worksheet titled "Descriptive Statistics."
• Use the Data Analysis - Descriptive Statistics tool, and place the results on the worksheet. We did not cover this in class so here is an explanation. For the "input range" select the "Data" values in the worksheet. Check the dialog box item, "Summary statistics" to generate a set of statistics in your worksheet. The "Descriptive Statistics" tool provides a quick and easy way to get a first look at your data.

• Use the TRACWAY.XLS file, "V1 Engines" worksheet.
• Create an XY Scatter plot of the samples.
• Using Data Analysis "Histogram" tool, identify the regression coefficients and write down the regression equation on your printout.
• Using the regression equation, compute the predict the values for sample # 51 and #52.

• Using the TRACWAY.XLS file, "Time to Pay Suppliers" worksheet
• Create an XY Scatter plot (hint - you may have to convert the X values into an acceptable format)
• Use the Data Analysis - Regression tool to find the regression equation and write out the full equation on your print out. Include the residual plots and line fit plots on your output. NOTE: Excel will overlay these two charts. To receive credit, you'll need to drag them to separate places on the worksheet so that both can be seen in their entirety when the worksheet is printed out.
• Interpret and comment on the R-squared value and use the residual plots to comment on the regression fit. Write your comments on your print out.
• Perform a Non-Linear Regression Analysis using the "trick" presented in lecture. You will need to convert the dates to a sample # (e.g. 1, 2, 3, 4, …). Then add an X-Squared term and repeat the regression as a 2^nd-order polynomial.

Use the TRACWAY.XLS file, "II1 Mower Power Unit Sales".

In this problem, you will try to determine a prediction equation for "World" sales based upon SA, Europe and Pacific. In other words, leaving out the U.S. and China. To do this requires a multiple regression analysis. You will need to re-arrange the data so that you can perform the multiple regression. Also, when pasting the values of the World column to another location in the spreadsheet, the values will be 0, because they are calculated by relative formulas. To avoid this problem, when you paste the selected cells, choose "Paste Special" and then choose "Values".

Determine a prediction equation for Y based on SA, Europe and Pacific regions only. Write down the multiple regression equation

Comment on the model quality/accuracy using the statistics or charts (e.g. residual plots) provided by Excel.

• Use the TRACWAY.XLS file, "Single Factor ANOVA" worksheet. Perform a single-factor ANOVA and determine whether to accept or reject the null hypothesis. Remember that the null hypothesis is that the means of the groups are the same. The alternative hypothesis is that at least one mean is statistically different from the others.