For his Research Methods project, Michael had 50 students complete the Selfism test, which measures narcissism. Narcissism is neurotic self-love. With an additional question, Michael determined that 27 students were first-born children and 23 were second-born children. All the participants were tested during the morning.

Identify:

a. the dependent variable

b. the independent variable and the names of the levels

c. a controlled extraneous variable