The average length of time customers spent on waiting at ABC Store's check-out counter before a new P.O.S.

system was installed was 5.3 minutes. A sample of 49 customers randomly selected at

the check-out counter after the new P.O.S. system was installed showed that the average

waiting time was 5.8 minutes with a sample standard deviation of 2.3 minutes. We wish

to determine if there has been a significant increase (from 5.3 minutes) in the average

waiting time after the P.O.S. system was installed. Take = 0.05.

15. Write appropriate null and alternate hypothesis.

16. Determine the critical value for this test.

17. Calculate test statistic.

18. Based on above information, what is your conclusion of the test?

19. Construct a 95% confidence interval for the average waiting time after the

new P.O.S. system was installed.