Ellen Decides to Study Overweight People

Ellen decides to study overweight people. She designs her study so that she will observe overweight and normal people eating in restaurants to see if there are differences in what
They order, how quickly they eat, and how much they eat. The diners will not know they
Are being observed. Ellen's research design employs the ______ method.

A) survey
B) experimental
C) naturalistic observation
D) case-study