A new drug for lowering blood pressure is tested. One group…
A new drug for lowering blood pressure is tested. One group of 15 patients are given this drug, and their blood pressure levels are measured after 1 hour. The second group of another 15 patients are given a placebo (they don’t know this), and their pressure levels are measured as well. To test the effect of the drug, we test if there is significant difference of these two data sets. Here is the summary of the blood pressures: Drug group Sample mean 135 Sample s.d. 20 Placebo group Sample mean 145 Sample s.d. 25 In this situation, we might assume that population variances are equal