. While there is no direct scientific measure of stress, some physical properties of the body that are believed to be related to stress include pulse rate, blood pressure, breathing rate, brain waves, muscle tension, skin resistance and body temperature. Some researchers claim that music can be relaxing and therefore can reduce stress. Fifteen patients who claim to be suffering from job related stress were selected at random. The resting pulse rate (in beats per minute) was

1. While there is no direct scientific measure of stress, some physical properties of the body that are believed to be related to stress include pulse rate, blood pressure, breathing rate, brain waves, muscle tension, skin resistance and body temperature. Some researchers claim that music can be relaxing and therefore can reduce stress. Fifteen patients who claim to be suffering from job related stress were selected at random. The resting pulse rate (in beats per minute) was obtained before each person participated in a month-long, music-listening, relaxation-therapy program. The resting pulse rate was also taken after the relaxation-

therapy program ended.a Let µ1 denote the resting pulse rate of stressed individuals after

taking the relaxation-therapy program and let µ2 denote the resting pulse rate of stressed individuals before taking the relaxation-therapy program. Also let µD = µ1 − µ2. Tables 1 and 2 present the descriptive statistics and the Shapiro-Wilk normality test for the difference (After − Before) in resting pulse rat

(a) Test, at the 1% level of significance, whether the relaxation-therapy program is effective in reducing the resting pulse rate for stressed individuals. Make sure you show all your workings in the 6 steps below.

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(b) Calculate the 95% confidence interval for µD.