Question

Several recent studies have suggested that people who suffer from abnormally high blood pressure can benefit from regular exercise. A medical researcher decides to test her belief that walking briskly for at least half an hour a day has the effect of lowering blood pressure. She conducts a small pilot study. If results from it are supportive, she will apply for funding for a larger study. She randomly samples three of her patients who have high blood pressure. She measures their systolic blood pressure initially and then again a month later after they participate in her exercise program. The table shows the results.

Subject	Before	After
1	150	130
2	165	140
3	135	120

Do a significance testing with a 95% confidence level.

1. Compute the difference, xd between the after and before observations for each sample.
2. Compute the sample mean difference, xd
3. State the hypotheses

H0:

Ha:

4. Compute for the test statistic.

se=

t=

5. Draw the necessary normal curve.

Answer 1

Solution: Before (di) 150 165 1135 After (dz) | 130 140120 d=dinda 20 25 15 b> Sample mean, du Ed 20+25+1S = 60 3 d=20 3 c) Hypothesis: Hoi Mdzo Haild &0 d rest Statistic 20-0 t= nou sirn 56.9282 ta6.9282 [is: (Rin? SEE slin 5 = 2.8867 & fri_203² 3 유의 SE = 2.8867 35 5 ey p-value using t-table P=0.0202 Since , p-value Looos, Reject Ho -0.0202 0.0202