Question

A random sample of size 13 is selected from men with hypertension. For each person, systolic blood pressure was measured right before and one hour after taking the medicine. The mean reduction of the blood pressures was 10.1 and the standard deviation of the difference was 11.2. Test if there is sufficient evidence to conclude that the hypertension medicine lowered blood pressure. What is the value of the test statistic (round off to second decimal place)

Answer 1

Yes, hypertension drugs lowers blood pressure.

Explanation:

Claim: The hypertension medicine lowered blood pressure.

The null and alternative hypothesis is

H0:\mu_{d}\geq 0

H1:\mu_{d}< 0

Level of significance = 0.05

Sample size = n = 13

Sample mean of difference = \bar{d} = 10.1

Sample standard deviation of difference = s_{d} = 11.2

Test statistic is

t=\frac{\bar{d}}{s_{d}/\sqrt{n}}

t = ((10.1) / (11.2 /squre root of 13)) = 3.251

Degrees of freedom = n - 1 = 13 - 1 = 12

Critical value =2.179( Using t table)

Test statistic | t | > critical value we reject null hypothesis.

In Conclusion: The hypertension medicine lowered blood pressure