Question

Mr. Williams is a chef at a restaurant, and he would like to add a new dessert to his menu. He decides to conduct a survey in order to help him make the decision about what type of dessert to add. Which of the following sampling techniques should Mr. Williams use in order to obtain the most representative sample of survey respondents?
A.
Mr. Williams should ask all the guests at the restaurant who order chocolate cake for dessert.

B.
Mr. Williams should ask all the children who visit the restaurant over the course of a week.

C.
Mr. Williams should ask at least one hundred randomly-chosen guests at the restaurant over the course of a week.

D.
Mr. Williams should ask one table of guests during lunch and one table of guests during dinner.

Answer 1

C. Asking at least 100 randomly chosen guests over a week is best. Random sampling of a reasonably large number reduces selection bias and is more likely to represent the restaurant's overall customers.

(A) is biased toward chocolate-cake lovers, (B) is biased toward children, and (D) is a very small, clustered sample that may not be representative.