In an article in the Journal of Management1 Wright and Bonett study the relationship between voluntary organizational turnover and such factors as work erformance1 work

In an article in the Journal of Management1 Wright and Bonett study the relationshipµ between voluntary organizational turnover and such factors as work µerformance1 work satisfaction1 and company tenure. As µart of the study1 the authors compare work performance ratings for "stayers" (employees who stay in their organization) and "leavers" (employees who voluntarily quit their jobs). Suppose that a random sample of 175 stayers has a mean performance rating (on a 20-point scale) of 1 = 12.8, and that a random sample of 140 leavers has a mean performance rating of 2 = 14.7. Assuming these random samples are independent and that σ1 = 3.7 and σ2 = 4.5:
a. Let µ1 be the mean performance rating for stayers1 and let µ2 be the mean performance rating for leavers. Use the sample information to calculate a 99 percent confidence interval for µ1 - µ2. Based on this interval1 can we be 99 percent confident that the mean performance rating for leavers is greater than the mean performance rating for stayers? What are the managerial implications of this result?
b. Set up the null and alternative hypotheses needed to try to establish that the mean performance rating for leavers is higher than the mean performance rating for stayers.
c. Use critical values to test the hypotheses you set up in part b by setting a equal to .101 .05. .01. and .001. How much evidence is there that leavers have a higher mean performance rating than do stayers?