In: Statistics and Probability
The Graduate Management Admission Test (GMAT) is a test required for admission into many masters of business administration (MBA) programs. Total scores on the GMAT are normally distributed. The Graduate Management Admission Council, who administers the test, claims that the mean total score is 580. Suppose a random sample of 8 students took the test, and their scores are given below.
640 |
610 |
560 |
610 |
570 |
680 |
670 |
560 |
A. Use α = .05 to test the claim that the mean total score is different from 580. Show all six steps.
B. Use the data above and α = .05 to test the claim that the mean total score is higher than 580. Show all six steps. Do you draw the same or a different conclusion? Why?
C. The Wendy’s in Sylva claims that the mean waiting time in the drive through line is less than 3.5 minutes at lunchtime on weekdays. A random sample of 30 customers has a mean of 3.4 minutes with a sample standard deviation of 1.2 minutes. If α = 0.05, test the restaurant’s claim.
D. Think about questions A and C. We’re using a sample to test the claim of an organization. Would the organization (the GMAT firm and/or the Wendy’s in Sylva) need to test a sample to find the average score or time? Why or why not?