Exam 12: Inference About Comparing Two Populat

Starting Salary In testing the hypotheses vs. , two random samples from two populations of college of business graduates majoring in global marketing and international business produced the following statistics regarding their starting salaries (in $1000s): , , , , , and . (Assume the salaries have normal distributions.){Starting Salary Narrative} What conclusion can we draw at the 5% significance level?

In testing for the differences between the means of two independent populations where the variances in each population are unknown but assumed equal, the degrees of freedom is:

The expected value of is .

Unless we can conclude that the population variances are equal, we cannot use the pooled variance estimate.

Aptitude Test Scores Two random samples of 40 students were drawn independently from two populations of students. Assume their aptitude tests are normally distributed (total points = 100). The following statistics regarding their scores in an aptitude test were obtained: . {Aptitude Test  Scores Narrative} Explain how to use the 95% confidence interval to test the hypotheses at a = .05.