Mary's newborn son was given the Apgar test at 1 minute and again at 5 minutes after birth. If he received a perfect score both times, what would the first and second Apgar scores be, respectively:

An independent variable

a. has at most two levels. b. can have any number of levels. c. is never a manipulated variable. d. cannot be a qualitative variable.

All social psychological research must begin with a(n)

a. control group. b. subject variable. c. question. d. independent variable.