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. In testing if there is sufficient evidence to conclude that the hypertension medicine lowered blood pressure, what is the p-value (round off to fourth decimal place)? Assume normal population. 1 pts Question 4 Pooled variance is used for an inference about two means for two small independent samples when we assume normal population with equal variance. True O False

Answer 1

3) Here we have:

Sample mean of difference(x̅_d )=   10.1
Sample standard deviation of difference(s_d )=   11.2
n =   13

Now

Hypothesis:  
Ho : µd = 0
H1 : µd > 0

Test statistic:

T test
t = (x̅_d)/(s_d/√n) =10.1/ 11.2/√13=3.25

At n=13 df =   13-1=12

P-value = TDIST( 3.25, 12, 1 ) = 0.003478 $\approx$ 0.0035

Hence the p value is 0.0035 (Ans)

p-value < α, Reject the null hypothesis.

There is sufficient evidence to conclude that the hypertension medicine lowered blood pressure.

4) The statement is TRUE