Question

A school is conducting a survey to determine the average number of hours students spend on homework each week. They plan to survey 50 students from a total of 600 students at the school. The principal wants to make sure that the sample selected provides a valid representation of all grade levels (6th, 7th, and 8th grades). Which of the following sampling methods would be the most appropriate to ensure the survey results are valid and represent all grade levels equally?

A.
Randomly select a total of 50 students from the entire school, without considering the grade level of the students.

B.
Randomly select a total of 50 students from the entire school (6th, 7th, and 8th grades), ensuring that each grade level is equally represented in the sample.

C.
Select a total of 50 students who have the highest grades in the school, assuming that they will provide the most reliable data.

D.
Select a total of 50 students who have volunteered to participate in the survey, assuming that they are more likely to respond accurately.

Answer 1

B. Randomly select a total of 50 students from the entire school (6th, 7th, and 8th grades), ensuring that each grade level is equally represented in the sample.

Explanation: This is a stratified random sample that forces representation from each grade, avoiding under- or over-representation. Option A (simple random) might by chance give unbalanced grades, C is biased (high-achievers only), and D has volunteer bias.