Question

a principal wants to find out how many hours per week the students in the school spend on exercise. which sample is likely to be most representative of the student population?
all students who play a sport on a school team
all students whose last name begins with a randomly selected letter
every fifth student from each grade from a list of registered students
every fifth female student who enters the school in the morning

Explanation:

A representative sample must reflect the entire student population without bias. The first option only includes student athletes, which is a biased subset. The second option only includes students with last names starting with a random letter, which may not evenly represent all demographic groups. The fourth option only samples female students arriving in the morning, excluding male students and those arriving at other times. The third option uses a systematic random sample across all grades, which evenly selects students from the full registered student body, making it the most representative.

Answer:

every fifth student from each grade from a list of registered students