Chapter 10.3, Problem 10.39ACA

Examining the “Monty Hall Dilemma.” In Exercise 3.133 (p. 186), you solved the game show problem of whether or not to switch your choice of three doors-one of which hides a prize-after the host reveals what is behind a door not chosen. (Despite the natural inclination of many to keep one’s first choice, the correct answer is that you should switch your choice of doors.) This problem is sometimes called the “Monty Hall Dilemma,” named for Monty Hall, the host of the popular TV game show Let’s Make a Deal. In Thinking & Reasoning (August 2007), Wichita State University professors set up an experiment designed to influence subjects to switch their original choice of doors. Each subject participated in 23 trials. In trial #1 , three doors (boxes) were presented on a computer screen, only one of which hid a prize. In each subsequent trial, an additional box was presented. so that in trial #23, 25 boxes were presented. After selecting a box in each trial all the remaining boxes except for one were either (1) shown to be empty (Empty condition), (2) disappeared (Vanish condition), (3) disappeared and the chosen box enlarged (Steroids condition) or (4) disappeared and the remaining box not chosen enlarged (Steroids2 condition). A total of 27 subjects were assigned to each condition. The number of subjects who ultimately switched boxes is tallied, by condition, in the table below for both the first trials and the last trial.

a. For a selected trial, does the likelihood of switching boxes depend on condition? Yes, for last trial

b. For a given condition, does the likelihood of switching boxes depend on trial number? Yes, for all conditions

c. Based on the results, parts a and b , what factors influence a subject to switch choices? Condition and Trial