Clark Heter is the industrial engineer at Lyons Products. He would like to describe whether there're more units produced on afternoon shift than on the day shift. A sample of 54 day-shift workers showed that the mean number of units produced was 345, with the standard deviation of 21. A sample of 60 afternoon-shift workers showed that the mean number of units produced was 351, with the standard deviation of 28 units. At the .05 significance level, is number of units produced on afternoon shift larger?