Question

A researcher conducts a double-blind experiment that tests whether a new drug is effective in reducing blood pressure.

During a three-month period the 200 randomly selected people in the treatment group take the new drug while the 200 randomly selected people in the control group take a placebo. The results show that 80 people in the treatment group continue to have high blood pressure, compared to 84 people in the control group.
a) Can we conclude that the drug is effective in reducing blood pressure? Explain your reasoning.
b) What percent of the treatment group continued to have high blood pressure after the​ three-month period?

Answer 1

a) Based on the information provided, it is not possible to conclusively determine whether the new drug is effective in reducing blood pressure. While there is a slightly lower percentage of people in the treatment group who continued to have high blood pressure compared to the control group, the difference is relatively small (4 people out of 200) and may not be statistically significant. Further analysis, such as calculating confidence intervals or conducting hypothesis testing, would be necessary to determine if the difference is statistically significant and if the drug is truly effective in reducing blood pressure.

b) The percentage of the treatment group who continued to have high blood pressure after the three-month period can be calculated by dividing the number of people who still had high blood pressure (80) by the total number of people in the treatment group (200) and multiplying by 100. Thus, the percentage of the treatment group who continued to have high blood pressure is:

(80/200) x 100 = 40%