Question: A major supermarket chain’s mean population waiting time to check out is 10.73 minutes. They have tried a new checkout arrangement with one waiting line and multiple checkout stations. In their new arrangement they sampled 100 customers, and their mean waiting time to check out was 9.53 minutes with a sample standard deviation of 5.8 minutes. Their hypothesis is that the mean waiting time with the new arrangement is less than with the previous arrangement. Write the hypothesis and the null: (Chapter 9)

a. Hypothesis:

b. Null:

c. At the .05 level of significance, what is the critical value from the chart?

d. If the test statistic is -2.0862, and p = 0.0198, do you reject or accept the null?

e. Why?

f. Did the new arrangement reduce checkout time at a statistically significant level?

g. Would you still make the same decision about the null at the 99% confidence level?

h. Why?