Chapter 11, Problem 11P

College athletes, especially males, are often perceived as having very little interest in the academic side of their college experience. One common problem is class attendance. To address the problem of class attendance, a group of researchers developed and demonstrated a relatively simple but effective intervention (Bicard, Lou, Mills, Bicard, & Baylot-Casey, 2012). The researchers asked each athlete to text his academic counsellor “in class” as soon as he arrived at the classroom. The researchers found significantly better attendance after the students began texting. In a similar study, a researcher monitored class attendance for a sample of $n=16$ male athletes during the first 3 weeks of the semester and recorded the number of minutes that each student was late to class. The athletes were then asked to begin texting their arrival at the classroom and the researcher continued to monitor attendance for another 3 weeks. For each athlete, the average lateness for the first three weeks and for the second three weeks were calculated, and the difference score was recorded. The data showed that lateness to class decreased by an average of $M_d=21$ minutes with $SS=2940$ when the students were texting.

a. Use a two-tailed test with $\alpha =.01$ to determine whether texting produced a significant change in attendance.

h. Compute a 95% confidence interval to estimate the mean change in attendance for the population.