Question

Johnny wants to know how many students in his school enjoy watching science programs on TV. He poses this question to all 26 students in his science class and finds that 75% of his classmates enjoy watching science programs on TV. He claims that 75% of the school's student population would be expected to enjoy watching science programs on TV. Is Johnny making a valid inference about this population? Yes, it is a valid inference because his classmates make up a random sample of the students in the school Yes, it is a valid inference because he asked all 26 students in his science class No, it is not a valid inference because he asked all 26 students in his science class instead of taking a sample from his math class No, it is not a valid inference because his classmates do not make up a random sample of the students in the school

Answer 1

The correct answer would be option D.
No, it is not a valid inference because his classmates do not make up a random sample of the students in the school

The population represents all of the students in the school. Apart from his science class there can be students in arts class, music class, literature class and so on. He used convenience sampling by just surveying the students of his science class. The students in science class are those who are interested in science and related topics so these students will be more inclined towards watching a science program. Thus the survey of Johnny does not yield valid result and his inference is not valid.

Thus, option D is the correct answer.