A group interested in the result of an upcoming ballot initiative about the public school system is conducting a poll to find the likely outcome. They randomly select registered voters with school-age children from the voting population. The first question in the poll ascertains whether or not the participant is a likely voter and only those people who plan to vote are asked to complete the poll. What is the flaw in this sample?

Question

Quizplus · Accepted Answer

Narrowing the possible sample group to include only those voters who have school-age children produces results of how intended voters with the greatest interest in the issue are likely to vote, but not how all intended voters are likely to vote. The vote is not limited to citizens with school-age children, so the poll, to be accurate, must not be limited in that fashion.

A Group Interested in the Result of an Upcoming Ballot