. In a medical study conducted to test the suggestion that daily exercise has the effect
of lowering blood pressure, a sample of eight patients with high blood pressure was
selected. Their blood pressure was measured initially and then again a month later
after they had participated in an exercise programme. The results are shown in the
table below:
Patient 1 2 3 4 5 6 7 8
Before 155 152 146 153 146 160 139 148
After 145 147 123 137 141 142 140 138
(a) Explain why a standard two-sample t-test would not be appropriate in this investigation to test the suggestion that daily exercise has the effect of lowering blood
pressure. [2]
(b) Perform a suitable t-test for this medical study. You should clearly state the null
and alternative hypotheses.