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. Using this data, find the 90% confidence interval for the true difference in blood pressure for each patient after taking the new drug. Assume that the blood pressures 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) 195 167 197 187 187 186 204 178 172 Blood pressure (after) 181 158 174 172 162 162 185 167 146 Step 2 of 4 : Calculate the sample standard deviation of the paired differences. Round your answer to six decimal places.

Answer 1