Parents from MADD (Mothers against Drunk Driving) were recruited to take part in a study, along with parents who were not members of the organization. The parents were equally assigned to one of four groups. They read a message about elevating the non-accompanied driving age from 16 to 18 from either an expert or non-expert source who supported his position with either strong or weak arguments. Participants then rated how likely they would be to vote for a law mandating the elevated driving age on a Likert scale. Parents from MADD were more likely to vote for the law. Strong arguments were more persuasive than weak arguments. Parents were persuaded by strong arguments when the source was not an expert, but they were equally persuaded by strong and weak arguments when the source was an expert.
a. Was this a true experiment or quasi experiment?
b. What was (were) the independent variable(s) and levels (of each)?
c. What was the design? Was it within or between subjects?
d. What was (were) the dependent variable(s)?
e. Were there any main effects, and if so, what were they? (If none are mentioned explicitly, assume there were none.)
f. Was there an interaction? If so, describe it in words.