Part A- A researcher posts a magazine advertisement offering $30 in exchange for participation in a short study. The researcher accepts the first three people who respond to the advertisement. Which of the following statements is true about the sample?

A. It is not a valid sample because it is not a random sample of the population.

B.It is a valid sample because the first three people were selected to participate.

C. It is a valid sample because money was offered to participants.

D. It is not a valid sample because it is only a short study.

Part B- The language arts teacher wants to know whether the students in the entire school prefer a debate or an speech. The teacher draws a random sample from the following groups:

• All teachers in the school
• All boys in each grade
• All students in the speech club
• All students in each grade

Which groupbestrepresents the population she should take a random sample from to get the best results for her survey?

A. All teachers in the school

B. All boys in each grade

C. All students in the speech club

D. All students in each grade

Part C- Jerome wants to know how many students in his school enjoy watching comedy programs on TV. He poses this question to all 28 students in his math class and finds that 70% of his classmates enjoy watching comedy programs on TV. He claims that 70% of the school's student population would be expected to enjoy watching comedy programs on TV. Is Jerome making a valid inference about this population?

A. Yes, it is a valid inference because his classmates make up a random sample of the students in the school

B. Yes, it is a valid inference because he asked all 28 students in his math class

C. No, it is not a valid inference because his classmates do not make up a random sample of the students in the school

D. No, it is not a valid inference because he asked all 28 students in his math class instead of taking a sample from his science class