Question

In Meijer supermarket, the customer’s waiting time to check out is approximately normally distributed with a standard deviation of 2.5 minutes. A sample of 25 customer waiting times produced a mean of 8.2 minutes. Is this evidence sufficient to reject the supermarket’s claim that its customer checkout time averages no more than 7 minutes? Complete this hypothesis test using the 0.02 level of significance.

H0: ?= 7 vs. Ha: ?>7.

a) Calculate the value of the test statistic, z⋆.

b) Find the p-value of the test statistic (for p-value approach). Mark and label the test statistic, z*; and shade the area represented by the p-value/values on the graph.

c) Determine the critical region and the critical value(for classical approach). Mark and label the critical value/values; shade the area represented by the level of significance ? = 0.02 on the graph.

d) State the decision rule for the p-value approach.

e) State the decision rule for the classical approach.

f) State the decision (reject or fail to reject H0), and the conclusion you would reach based on the evidence provided.

Answer 1

(f) we reject null hypothesis There is sufficient evidence to conclude t hathat supermarket’s that its customer checkout time averages more than 7 minutes