Today’s question comes from the GMAT. It’s Critical Reasoning Practice Question #7 in The Official Guide for GMAT Verbal Review, 2nd Edition (page 118).
A researcher discovered that people who have low levels of immune-system activity tend to score much lower on tests of mental health than do people with normal or high immune-system activity. The researcher concluded from this experiment that the immune system protects against mental illness as well as against physical disease.
The researcher’s conclusion depends on which of the following assumptions?Read More