Question

what is wrong with each of these study designs, given the hypothesis? Why is this study design inappropriate for testing the stated hypothesis? Hypothesis: Blueberries reduce the risk of cancer. Study Design: 50 healthy women will be randomly divided into 2 groups. One group will be instructed to eat blueberries with each meal and the other group will be instructed to avoid blueberries entirely. At the end of 3 months, the number of breast cancer cases in each group will be assessed.

Answer 1

Hi,

The hypothesis is to check whether blueberries can help avoid cancer development. The study has taken healthy individuals and asked few to eat blueberries. The study time of 3 months is too short for the cancer to develop. Cancer takes years to develop and to be able to detect. If there is indeed any effect of blueberries on cancer, within 3 months it may not be detected.

The other diet if the individuals continues as normal so there are too many variables which might cause the proposed effect.

Eating prescribed blueberries may not be sufficient to cause the proposed effect. There is not data as to how many blueberries one must eat.

Hence the study has experimental errors.