Recall from Chapter 1 (refer to page 30) that the Focus database and Focus sample contain information on the undergraduate students at the University of Wisconsin – Eau Claire (UWEC). Now would be a good time for you to review the discussion about these data sets. Open the Focus sample worksheet (FocusSample) in the technology of your choice and do the following.
a. At the 10% significance level, do the data provide sufficient evidence to conclude that a difference exists among mean cumulative GPA for freshmen, sophomores, juniors, and seniors at UWEC? Use the one-way ANOVA procedure.
b. Obtain individual normal probability plots and the sample standard deviations of the GPAs of the sampled students in each class level. Based on your results, decide whether conducting a one-way ANOVA test on the data is reasonable.
c. Perform a residual analysis of the GPAs by class level. Based on your results, decide whether conducting a one-way ANOVA test on the data is reasonable.
d. Repeat parts (a)–(c) for mean cumulative GPA by college.