A researcher plans a school-district-wide study to compare Methods A and B of increasing physical activity in third graders. Which of the following procedures would be MOST appropriate for selecting a sample?
A) Obtain permission from a cooperative principal to select the sample from students in her school.
B) Require all students enrolled in physical education classes to serve as subjects.
C) Use students from one school as subjects to receive the Method A treatment and students from a second school to receive the Method B treatment.
D) Define the population as all students in the district and select a random sample.

Question

Quizplus · Accepted Answer

Defining the population as all students in the district and selecting a random sample would be the most appropriate procedure for this study, as it would provide a representative sample of the entire population being studied. A random sample would avoid any potential biases or confounding factors that could occur with the other options, such as selecting students only from one school or requiring all students in physical education classes to participate.

A Researcher Plans a School-District-Wide Study to Compare Methods a and B