Use this information to answer Question 1 to Question 5: 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 64 customers randomly selected at the check-out counter after the new P.O.S. system was installed showed that the average waiting time was

6.1 minutes with a sample standard deviation of 3.3 minutes. We wish to determine if there has been a signi cant increase (from 5.3 minutes) in the average waiting time after the P.O.S. system was installed. Take = 0.05.

1.(2 points) Write appropriate null and alternate hypothesis.

2.(2 points) Determine the critical value for this test.

3.(3 points) Calculate test statistic.

4.(2 points) Based on above information, what is your conclusion of the test?

5.(3 points) Construct a 95% con dence intervalfor the average waiting time after thenew P.O.S. system was installed.