An industrial psychologist has a stress test that is used to determine the amount of stress that managers are under. A value of 80 or higher indicates “high stress.” The industrial psychologist believes that the managers at a large, profitable pharmaceutical firm are not under “high stress” and that the average stress index is less than 80 for managers of the company. A random sample of 50 managers is selected, and their stress index was recorded. Assume that the population standard deviation is 10.15. See the file “Stress Index for Managers”
If you perform a statistical test, try a one-sample z-test.
z = (sample mean - population mean)/(standard deviation divided by the square root of the sample size)
Population mean = 80
Sample mean = ? (I don't see one listed)
Standard deviation = 10.15
Sample size = 50
Once you have the z-test statistic, you can go from there to test your hypothesis.
I hope this helps.posted by MathGuru