11.14 Example 11.1 looked at a study comparing students who use Facebook and students who do not use Facebook (“Facebook and Academic Performance,”

Computers in Human Behavior [2010]: 1237–1245).

In addition to asking the students in the samples about GPA, each student was also asked how many hours he or she spent studying each day. The two samples (141 students who were Facebook users and 68 students who were not Facebook users) were independently selected from students at a large, public Midwestern university. Although the samples were not selected at random, they were selected to be representative of the two populations.

For the sample of Facebook users, the mean number of hours studied per day was 1.47 hours and the standard deviation was 0.83 hours. For the sample of students who do not use Facebook, the mean was 2.76 hours and the standard deviation was 0.99 hours. Do these sample data provide convincing evidence that the mean time spent studying for Facebook users at this university is less than the mean time spent studying by students at the university who do not use Facebook? Use a significance level of 0.01.