Which of the Following Yields a Simple Random Sample

Multiple Choice

Which of the following yields a simple random sample?

A) All students in a class are grouped according to their gender. A random sample of 8 is selected from the males and a separate random sample of 7 is drawn from the females.
B) The best 15 students, according to the opinion of the instructor, in a class are selected.
C) The names of 50 students in a class are written on 50 different pieces of paper and put in a hat. The first 15 pieces of paper are selected blindly one at a time after shuffling the papers thoroughly and each of the selected pieces is placed back into the hat before the next piece is selected.
D) All students in a class are divided into groups according to the rows in which they are seated. One of the groups is randomly selected.