Hypothesis testing for two population means.
Clark Heter is an industrial engineer at Lyons Products. He would like to conclude whether there are more units produced on the afternoon shift than on the day shift. A sample of 54 day-shift workers showed that mean number of units produced was 345, with a standard deviation of 21. A sample of 60 afternoon-shift workers showed that mean number of units produced was 351, with the standard deviation of 28 units. At the .05 significance level, is the number of units produced on the afternoon shift larger?