Answer:
The study group was skewed
Step-by-step explanation:
It is often touted that doing volunteer work would enhance life and life quality. While this is believed to be true and my have some substance to it, the design flaw of the experiments made it almost not credible.
The test group that was used were women who were engaged in volunteer work already. It has been shown that women are already living longer than men. To correlate the fact that people live longer who do volunteer work when only using a certain demographic may not be the most sound conclusion to make.