Question

which of the following is the best way of selecting a random sample from students at king middle school?
select every student from one grade.
use the student directory, pick one students name by chance, and then pick another students name.
pick every tenth person who arrives at school by bus.
use the student directory, toss a number cube, start from that name, and select every tenth person.

Explanation:

A random sample should be representative of the entire population. Selecting every student from one grade only represents that grade, not the whole school. Picking only two students (as in the second option) is too small a sample. Picking every tenth person who arrives by bus only represents bus - riding students. Using the student directory, tossing a number cube (random start) and then selecting every tenth person (systematic random sampling) gives a more representative sample of all students.

Answer:

Use the student directory, toss a number cube, start from that name, and select every tenth person.