The authors of the paper “Illicit Use of Psychostimulants among College Students” (Psychology, Health & Medicine [2002]: 283–287) surveyed college students about their use of legal and illegal stimulants.

The sample of students surveyed consisted of students enrolled in a psychology class at a small, competitive college in the United States.

a. Was this sample a simple random sample, a stratified sample, a systematic sample, or a convenience sample? Explain.

b. Give two reasons why the estimate of the proportion of students who reported using illegal stimulants based on data from this survey should not be generalized to all U.S. college students.