A doctor wants to know if a blood pressure medication is effective ...

Before

After

d = After - Before

161

158

-3

162

159

-3

165

166

1

162

160

-2

166

167

1

171

170

-1

d-bar =

-1.166666667

s =

1.834847859

Data:

n = n1 = n2 = 5

d-bar = -1.166666667

s (of d) = 1.834847859

Hypotheses:

Ho: d-bar ≥ 0

Ha: d-bar < 0

Decision Rule:

α = 0.05

Degrees of freedom = 5 - 1 = 4

Critical t- score = -2.131846782

Reject Ho if t < -2.131846782

Test Statistic:

SE = s/n = 1.83484785926972/√5 = 0.820568908

t = d-bar/SE = -1.16666666666667/0.820568908339411 = -1.421777811

p- value = 0.114075033

Decision (in terms of the hypotheses):

Since -1.421777811 > -2.132 we fail to reject Ho

Conclusion (in terms of the problem):

There is no sufficient evidence that the medication is effective