Problem 3: Self-checkout systems

Many grocery stores and large retailers such as Walmart and Target have installed self-checkout systems so shoppers can scan their own items and cash out themselves. A Walmart in Columbus, Ohio wanted to see how well liked these self-checkouts are and how often customers use them. They randomly selected a sample of 15 days from their summer calendar and recorded the number of customers using their self-checkout registers. Below is the list of number of customers using this service during these 15 days.

120 108 119 115 118 92 118 94 106 106 112 101 120 108 95

Conduct a hypothesis test to determine whether the number of customers using the self-checkout system is different than 100 customers per day. Use a 5% significance level.

1) What type of hypothesis test is needed here? Explain the requirements of this test.

2) Is this a right tailed, left tailed or two-tailed test?

3) State the null and alternate hypotheses here. H_o : H₁ :

4) Find the critical value and the test statistics. State them here.

5) Find the p-value of the test and state it here.

6) Make a statistical decision and justify it based on your findings from above.

7) Interpret this statistical decision in the context of the problem.