A Visual Approach to SPSS for Windows 2nd Edition by Leonard Stern

Exercise 4

For this exercise, use the file 04Cars.sav available on the publisher's website for this text at the address http://www.pearsonhighered.com/stern2e. The data set is based on information obtained from Edmunds.com and is reprinted here with permission. Analyze the relation between a car's weight and the length of its wheelbase. In performing this analysis, do the following:
1. Form a scatterplot using the variable Weight as the y-variable and WheelBase as the x-variable. Include a best-fitting straight line in your scatterplot.
2. Perform a regression analysis for the two variables. From the output, answer the following questions:
a. Does the relation between the two variables appear to be linear
b. What is the r value for the relation
c. Is the relation between the two variables statistically significant
d. What is the equation of the best-fitting straight line that predicts weight from wheelbase
e. Do the assumptions of normality of the distribution of residuals and homogeneity of residuals appear to be satisfied Explain how you answered this question.