An experiment involves selecting a random sample of 256 middle managers. We would like to know the mean salary ...

     An   experiment involves selecting a random sample of 256 middle managers. We   would like to know the mean salary (annual income). The sample mean salary is   45,000, and the sample standard deviation is $2,000. Calculate the 95%   confidence interval, showing the confidence limits. Hint, because the sample   size is greater than 30, we use the Z factor for 95%.