Researchers were interested in comparing students at private universities and students at public universities with respect to how much time they spent working in a typical week. They e-mailed a survey to 1,000 students enrolled at a particular private university and to 2,000 students enrolled at a particular public university. Data from the 400 private university students who responded to the survey and the 900 public university students who responded to the survey were used to determine that there was a significant difference in the mean number of hours worked in a typical week.