Question

select the correct answer. a school supervisor wants to determine the percentage of students that bring their lunch to school. which of the following methods would assure random selection of a sample population? a. the supervisor should survey all of the students enrolled in the school. b. the supervisor should randomly select one grade level and survey all of the students in that grade. c. the supervisor should select one grade level and survey randomly selected students from that grade. d. the supervisor should randomly select students from all grade levels taught at the school.

Explanation:

To ensure random selection of a sample population, we need a method that gives every student an equal chance of being selected, regardless of grade level.

• Option A: Surveying all students is a census, not a sample, so it doesn't involve sampling.
• Option B: Selecting one grade level and surveying all students in that grade is a cluster sample but only from one grade, not random across all students.
• Option C: Selecting one grade level and then randomly sampling from that grade still limits the sample to one grade, not the entire student population.
• Option D: Randomly selecting students from all grade levels ensures that every student in the school (across all grades) has an equal probability of being chosen, which is the definition of a simple random sample (or a random sample from the entire population).

Answer:

D. The supervisor should randomly select students from all grade levels taught at the school.