College Admissions Administrators at a University Are Reevaluating Their Entrance

Multiple Choice

College admissions administrators at a university are reevaluating their entrance requirements.They believe that the mean GPA for graduating high school seniors has increased dramatically over the last decade.They randomly sample 85 records of graduating seniors from 10 years ago (sample 1) and find an average GPA of 2.68.An independent random sample of 80 current graduating seniors yields an average GPA of 2.94.If the population variance of high school GPAs is 0.2601, find a 95% confidence interval for the difference in population mean GPA over the last decade.

A) (-0.42, -0.10)
B) (-0.29, -0.13)
C) (-0.36, -0.16)
D) (-0.46, -0.05)