Asked by Amy

A survey was mailed to a total of 400 students; 100 were randomly selected from each of the freshman, sophomore, junior and senior classes last semester. What sampling method was used?
Answered by MathGuru
There are many different types of sampling methods. Check them out and see which one closely fits your scenario.
Answered by Grace
Let smokers =A.
Gum chewers=B
n(AuB)= n(A) + n(B) -n(AnB).
100 + 150 - 75
=250-75=175
neither =400-175=225