Do graduates of undergraduate business programs with different majors tend to earn disparate average starting salaries? Consider the data given in the file P12_10.XLS. 

a. Is there any reason to doubt the equal-variance assumption made in the one-way ANOVA model in this particular case? Support your response to this question.

b. Assuming that the variances of the four underlying populations are indeed equal, can you reject at the 10% significance level that the mean starting salary is the same for each of the given business majors? Explain why or why not.

c. Generate90% confidence intervals for all pairs of differences between means. Which of these differences, if any, are statistically significant at the 10% significance level?