Senior management of a certain consulting services firm is concerned about a growing decline in the organization’s productivity. In an effort to understand the depth and extent of this problem, management would like to estimate the average number of hours\its employees spend on work-related activities in a typical week. The frame of virtually all of the firm’s full-time employees, including the employees’ self-reported amounts of time typically devoted to work activities each week, is provided in P8_35.XLS. 

a. What sample size would be required for management to be approximately 95% sure that its estimate of the average number of hours the employees spend on work-related activities in a typical week is within 6 hours of the true mean? Assume that management’s best estimate of the population standard deviation o is 10 hours per week.

b. How does the answer to part a change if management want its estimate to be within 3 hours of the actual population mean? Explain the difference in your answers to parts a and b.