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 95% 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
BP before	174	187	195	193	191	165	193	188	177
BP after	148	180	185	169	178	149	185	170	170

Step 1 of 4 : Find the point estimate for the population mean of the paired differences. Let x1 be the blood pressure before taking the new drug and x2 be the blood pressure after taking the new drug and use the formula d=x2−x1 to calculate the paired differences. Round your answer to one decimal place.

Step 2 of 4: Calculate the sample standard deviation of the paired differences. Round your answer to six decimal places.

Step 3 of 4: Calculate the margin of error to be used in constructing the confidence interval. Round your answer to six decimal places.

Step 4 of 4: Construct the 95% confidence interval. Round your answers to one decimal place.

Answer 1