Suppose, to select a sample from a population of 3000 persons, the following procedure is followed. The names of the people are written on identical, square pieces of thin cardboard measuring one inch on a side, and these pieces of cardboard are then tumbled in a clothes dryer (with the heat shut off). After 30 minutes, a blindfolded person reaches in and withdraws a selected number of names. What can be said about this sample?
A) The sample is probably biased because clothes dryers are not supposed to be used in collecting samples.
B) The sample is probably biased because people with shorter names would be selected first.
C) The sample is probably biased because the names on the top of the heap would be selected first.
D) The sample is probably biased because the names toward the front of the dryer would probably be selected first.
E) The sample is almost certainly random.

Question

Quizplus · Accepted Answer

This procedure of selecting a sample can be considered as a form of random sampling, as all the names have an equal chance of being selected. The clothes dryer does not introduce any systematic bias in the selection process, as the heat is shut off and the tumbling action of the dryer is designed to mix the pieces of cardboard randomly. Therefore, this sample can be considered almost certainly random.

Suppose, to Select a Sample from a Population of 3000