Homework B01:

Answers

Problem #5: 1. Some treatments cannot be hidden from the subjects. For example, if you want to compare one treatment of surgery to a standard drug treatment, there is no ethical way to keep the patient from knowing whether they have had surgery.

2. Some studies cannot be designed as experiments. If you want to study the effect of smoking on heart disease, you cannot force one group to smoke for, say, 10 years to compare them with another group that is forced not to smoke.

Problem #8: Even though polio was a frightening disease, it was not common. In order to make a meaningful and convincing judgment of whether the vaccine worked, you had to make sure to use a sample large enough to get several cases (e.g., more than 5 in the control group) of polio. If you used only 100 children in each group, and none of the 200 got polio, the study would show nothing.