The Essentials of Statistics 3rd Edition by Joseph Healey

Exercise 4

SW: Nationally, social workers average 10.2 years of experience. In a random sample, 203 social workers in greater metropolitan Shinbone average only 8.7 years, with a standard deviation of 0.52. Are social workers in Shinbone significantly less experienced?
(Hint: Note the wording of the research hypotheses. This situation may justify a one-tailed test of significance. If you chose a one-tailed test, what form would the research hypothesis take and where would the critical region begin?)