Question

1. A doctor wants to know if a blood pressure medication is effective in lowering blood pressure. Six subjects have their blood pressures recorded. After twelve weeks on the medication, the same six subjects have their blood pressure recorded again. For this test, only systolic pressure is of concern.

Patient	A	B	C	D	E	F
Before	161	162	165	162	166	171
After	158	159	166	160	167	169

1. Write H_o and H_a
2. Is this a right, left, or two-tailed test?
3. What is the p-value?
4. Do you reject or accept the null hypothesis at the 1% level?

Answer 1

we have to test that blood pressure medication is effective in lowering blood pressure.

that is we have to test that difference =after -before is less than ZERO hence

we have

sample size =n=6

sample mean of difference =m=-1.333

sample SD of difference=S=1.862

a)

b)

test is left tailed

c)

test statistics is given by

test is two tailed so

P-Value =P(Z<-1.754) =0.034

d)

since P value is greater than level of significance hence we fail to reject H0 Hence we do not have enough evidence to conclude that blood pressure medication is not effective in lowering blood pressure