Question

A pharmaceutical company claims that its new drug reduces systolic blood pressure. The systolic blood pressure (in millimeters of mercury) for nine patients before taking the new drug and 2 hours after taking the drug are shown in the table below. Is there enough evidence to support the company's claim?

Let d=(blood pressure before taking new drug)−(blood pressure after taking new drug) . Use a significance level of α=0.05 for the test. Assume that the systolic blood pressure levels are normally distributed for the population of patients both before and after taking the new drug.

Patient	1	2	3	4	5	6	7	8	9
Blood pressure (before)	148	171	160	183	187	165	186	166	198
Blood pressure (after)	142	154	151	166	180	148	167	151	185

Step 1 of 5:

State the null and alternative hypotheses for the test.

Step 2 of 5:

Find the value of the standard deviation of the paired differences. Round your answer to one decimal place.

Step 3 of 5:

Compute the value of the test statistic. Round your answer to three decimal places.

Step 4 of 5:

Determine the decision rule for rejecting the null hypothesis H0 . Round the numerical portion of your answer to three decimal places.

Step 5 of 5:

Make the decision for the hypothesis test

Answer 1

Count, N:	9
Sum, Σx:	120
Mean, x̄:	13.333333333333
Variance, s2:	23.5

Step 1 :

H0 : _d = 0

H1 : _d > 0

Step 2 :

Standard deviation Sd = 4.8

Step 3 :

Test statistic t = d-bar / (Sd / sqrt(n) ) = 13.33 / (4.8 / sqrt(9) )

= 8.331

Step 4 :

aplha = 0.05

t-critical = 1.86

t > t-critical

Reject H0

Step 5 :

We can conclude that the new drug reduces systolic blood pressure.