Question

A national survey of middle-school students asks which subject is most challenging. Which of these samples is a representative sample?
A.


372 sixth-graders in a certain town
B.


972 seventh-graders in a certain county
C.


619 eighth-graders in different states
D.


400 students from various states, representing different grades, 6–8

Answer 1

Answer:

The correct answer is D

Step-by-step explanation:

For a research sample to be described as representative , the sample must be a subset of the target population group and it must accurately reflects the features of the target population group.

In this question, the target population is the middle school students of a country,that is , grade 6-8 .

The survey is a national one ,that is , it covers the whole country .In order to obtain a representative samples of this particular survey, samples must be drawn from grade 6-8 and the samples must come from different parts of the country .This is why option D is correct.

The other option are not correct because , the samples are limited to only particular grades or particular towns or states.