Dr. Smith was interested in whether a new drug for Alzheimer's disease would
improve short-term memory among her patients. She also explored the effect of
daily exercise on memory, as well. She randomly and equally assigned her
patients to one of the six conditions - drug (a new drug or placebo) x frequency of
exercise (0 times per day, 1 time per day, or 2 times per day). After 3 months of
treatment, she measured the patients' performance on a short-term memory test
(such that higher scores indicated better performance on the test).
