Next Question Researchers investigated the physiological changes that accompany laughter. Ninety subjects (18-34 years old) watched film clips designed to evoke laughter. During the laughing period, the researchers measured the heart rate (beats per minute) of each subject, with the following summary results: x = 73.8, s = 5. It is well known that the mean resting heart rate of adults is 71 beats per minute. Complete parts a through d below. a. Set up Ho and Ha for testing whether the true mean heart rate during laughter exceeds 71 beats per minute. Choose the correct answer below. O A. Ho: H= 71 OB. Ho: H# 71 Ha: p# 71 Ha: H = 71 O C. Ho: H= 71 D. Ho: H=71 Ha: H 71 b. If a = 0.05, find the rejection region for the test. Choose the correct answer below. O A. Z> 1.96 O B. z> 1.645 O C. Z 1.645 or z 1.96 or z