Question

A researcher posts a newspaper advertisement offering $10 in exchange for participation in a short study. The researcher accepts the first 10

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 only a short study.
B. It is a valid sample because money is offered to participants.
C. It is a valid sample because the first 10 people were selected to participate.
D. It is not a valid sample because it is not a random sample of the population.

Answer 1

The correct answer is D: It is not a valid sample because it is not a random sample of the population.

For a sample to be valid and representative of the population, it should be selected randomly. In this case, the researcher accepted the first 10 people who responded to the advertisement. This is a non-random sampling method known as convenience sampling and is prone to biases.

The other statements are incorrect:

A) The length of the study does not affect whether the sample is valid.

B) Offering compensation does not automatically make the sample valid.

C) Selecting the first 10 people does not make the sample valid - it needs to be selected randomly.

So in summary, the key issue here is that the sample was not selected randomly from the population, making it not a valid representative sample.