Elaine conducts a psychology honors project to test the hypothesis that having greater social support is associated with greater academic success. she asks everyone living in her dorm to fill out a questionnaire. elaine should be aware that her data may not be representative of all college students because her research was based on:

Martha participates in a research study in order to receive extra credit for her psychology class. when she arrives in the research office she is given a can of what looks and tastes like beer, but which actually contains no alcohol. in the adjoining room martha's classmate karen is also participating in the study. karen receives a can of alcoholic beer. if the experiment was designed to test the effects of alcohol on concentration, then who is exposed to the independent variable?