Question

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?

It is not a valid sample because it is not a random sample of the population.
It is a valid sample because the first three people were selected to participate.
It is a valid sample because money was offered to participants.
It is not a valid sample because it is only a short study.

Answer 1

Hello!

A valid sample is a sample where everyone has a chance to answer

This is not valid because it was only the first three people not random selection

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

Hope this helps!

Answer 2

The first statement is the right answer.

Explanation:

The following statements is true about the sample:

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

Firstly, it is given that the researcher accepted the first three people who respond to the advertisement. This selection is not random. He just picked up the first three people rather than picking in some other way.

Secondly, due to the small size of people involved with the study, this is not valid also. For a valid result/sample, a good population size is needed.

Thus, this study is not valid and not random also.