Advantage Manufacturing, a manufacturer of above ground portable swimming pools, claims that “the average family can assemble the Advantage Pool within one hour” (patiostore.com). In a telephone survey of 50 randomly selected Advantage Pool buyers, you find that the average assembly time reported by those in the sample is 68.5 minutes. Is this sufficient evidence to reject Advantage’s claim? Set up a hypothesis test, using a 5% significance level. Assume the standard deviation of setup times for the population of Advantage Pool buyers is 24 minutes. As you proceed,
a. Show the null and alternative hypotheses.
b. State the appropriate decision rule.
c. Compute the sample test statistic, z stat.
d. Should the null hypothesis be rejected? Explain.