1. Employees in a large manufacturing plant worked an average of 62.0 hours of overtime last year, with a standard deviation of 15.0 hours. For a simple random sample of n 5 36 employees and x 5 the number of overtime hours worked last year, determine the z-score corresponding to each of the following sample means:
a. }x 5 55.0 hours
b. }x 5 60.0 hours
c. }x 5 65.0 hours
d. }x 5 47.0 hours
2. For the manufacturing plant discussed in Exercise 8.10, the union president and the human resources director jointly select a simple random sample of 36 employees to engage in a discussion with regard to the company's work rules and overtime policies. What is the probability that the average number of overtime hours last year for members of this sample would have been less than 65.0 hours? Between 55.0 and 65.0 hours?