Starbucks offers benefits to their employees that work
more than 20 hours per week. The CEO is proud of this new policy
and wants to ensure that the average worker works more than 20
hours a week. The company has decided to sample 10 employees and
ask them how many hours they work per week. The following are the
responses they received:
23, 18, 20,
26, 27, 30, 16, 18, 20, 28
Conduct the appropriate hypothesis test to see if the mean hours
worked per week is more than 20 hours based on these results.
(a) State the null and alternative hypotheses.
(b) Calculate the appropriate test statistic for this test. What
does this test statistic measure?
(c) Calculate the p-value for this test statistic.
(d) Starbucks has not decided on a value for alpha. Suggest a value
for alpha that would cause the company to believe that the mean
hours worked is more than 20 hours. Explain your choice for
alpha.
(e) Sketch the distribution of test statistic when the null is
true, and shade the area that corresponds to the p-value.