Use the guidelines to evaluate the study. Discuss flaws that you see in the study. A pharmaceutical company wants to test its new medication to lower blood pressure. It randomly selects 1000 people with high blood pressure and randomly assigns each person to one of two groups. The first group receives the medication for a month and also suggestions as to how to improve their diet. The control group receives a placebo medication and no dietary suggestions. At the end of the month each person's blood pressure is again taken. The average change in blood pressure is compared for the two groups.

Question

What will be an ideal response?

Answer 1

The source - the pharmaceutical company is not unbiased and should not be testing its own medication.
There is a confounding variable, the group taking the medication is also being given dietary suggestions. It will be impossible to know whether any difference in blood pressure between the two groups is due to the medication or to differences in diet between the two groups.