Robert is gathering data for his graduate research project. He targets psychology students as his participants. He randomly selects several psychology classes of which to administer his questionnaire. Which of the following is true about Robert's participants?

a. The students in the psychology classes represent the population and all the psychology students on campus also represent the population.
b. The students in the psychology classes represent the population and all the psychology students on campus represent the sample.
c. The students in the psychology classes represent the sample and all the psychology students on campus also represent the sample.

Robert graduate research project didn't state that all psychology students and classes are the sample he wants to use for his research. He only targets the Psychology students as his participants not sample. So the intuition from the question eliminates options B and C and the conclusion that can be drawn from the question above is that all the students in the psychology classes represent a portion of the sample Roberts wants to use to carry out his research just that he randomly chose some to be his participant.