Semester Two Practice Examinations, 2022 STAT2201 Question 2. [10 marks] A study investigated the effect of playing computer games on heart rate. Twenty eight individuals were recruited into the study and randomly assigned to play either an M- rated game or a G-rated game, with fourteen participants in each group. Each participant's heart rate was measured in a resting state before playing the video game and again after playing the video game for 20 minutes. The G-rated video game group had an average change (after before) in heart rate of 3.1 beats per minute (bpm) and the sample standard deviation of the change was 5.3 bpm. The M-rated video game group had an average change (after - before) in heart rate of 7.2 beats per minute (bpm) and the sample standard deviation of the change was 6.4 bpm. - (a) Does playing a G-rated video game increase the mean heart rate above the mean heart rate for the resting state? State the null and alternative hypotheses, and use an appropriate test statistic to determine the p-value (or provide a bound on the p-value). Based on the statistical test, what do you conclude? [4 marks] (b) How much more does playing M-rated video games increase heart rate compared to G-rated video games? Construct a 99% confidence interval for the difference in the mean increase in heart rate from the two video games. [4 marks] State the assumptions you implicitly made in your answer to part (b). [2 marks] Page 3 of 11