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 = 36 employees and x = the number of overtime hours worked last year, determine the z-score corresponding to each of the following sample means:
a. x‾ = 55.0 hours
b. x‾ = 60.0 hours
c. x‾ = 65.0 hours
d. x‾ = 47.0 hours