Question

Many Americans have high blood pressure which can lead to a number of serious conditions including heart attack and stroke. There are a number of drugs available to treat high blood pressure, but researchers are always seeking new ones with fewer side effects. In this experiment, researchers randomly selected 20 women from a pool with high-normal blood pressure to high blood pressure and measured their initial systolic blood pressure (in mm of Hg). They treated the subjects with an experimental blood pressure medicine for 4 weeks and then measured their blood pressure again after the treatment. They wanted to see if the medication decreased the systolic blood pressure of the patients.

A.) Are these samples in this data set paired samples, independent samples or a single sample?

B.) What kind of test would be best to use? (Mann-whitney, Paired t-test, Wilcoxon signed ranks, Two sample t-test, Anderson Darling, One sample t-test, the sign test, or a two-sample t-test)

C.) Using population parameters µ, θ, or p, identify the null and alternative hypothesis.

D.) What should the alpha (α) value be for this study?

E.) Which of the choices best matches your interpretation of the results for this statistical test?

The results were significant so we reject the null hypothesis and support the alternative

The results were not significant so we fail to reject the null hypothesis

The results were not significant so we reject the null hypothesis and accept the alternative

The results were significant so we fail to reject the null hypothesis

record.number	individual	treatment	blood.pressure
1	1	initial	148
2	2	initial	141
3	3	initial	162
4	4	initial	146
5	5	initial	146
6	6	initial	130
7	7	initial	147
8	8	initial	137
9	9	initial	152
10	10	initial	139
11	11	initial	130
12	12	initial	139
13	13	initial	145
14	14	initial	150
15	15	initial	167
16	16	initial	136
17	17	initial	134
18	18	initial	151
19	19	initial	144
20	20	initial	151
21	1	treatment	140
22	2	treatment	140
23	3	treatment	138
24	4	treatment	140
25	5	treatment	159
26	6	treatment	140
27	7	treatment	127
28	8	treatment	137
29	9	treatment	127
30	10	treatment	141
31	11	treatment	135
32	12	treatment	146
33	13	treatment	125
34	14	treatment	155
35	15	treatment	152
36	16	treatment	141
37	17	treatment	143
38	18	treatment	139
39	19	treatment	151
40	20	treatment	143

Answer 1

A.) Are these samples in this data set paired samples, independent samples or a single sample?

B.) What kind of test would be best to use? We shall be using a paired t-test comparing the Blood pressures of Initial and after treatment values.

C.) Using population parameters : Let denotes the population mean of the difference between the pre and post treatment values.

Null hypothesis: (The treatment did not give any effect on the blood pressure)

  (The blood pressure reduced after the treatment)

D.) What should the alpha (α) value be for this study?

E.) Which of the choices best matches your interpretation of the results for this statistical test?

The results were significant so we reject the null hypothesis and support the alternative