Question: Before/After treatment results. Captori is a drug designed to lower systolic blood pressure when subjects were tested with this drug, their systolic blood pressure readings (in mm of mercury) were measured before and after the drug was taken, with he results given in the accompanying table (based on data from essential hypertension: effect of an oral inhibitor of Angiotensin-Converting Enzyme, by MacGregor et al., British Medical Journal, vol 2.)

A) Use the sample data to construct a 99% confidence interval for the mean difference between the before and after readings.

B) Is there sufficient evidence to support the claim that captoril is effective in lowering systolic blood pressure