**Click on a door to begin**.

Number of Doors

Number Correct:

Number Incorrect:

Proportion Correct:

Stay Trials

Number Correct:

Number Incorrect:

Proportion Correct:

The results are very counterintuitive. For the three-door problem, if the contestant is correct on the first choice, then he or she will be incorrect after a switch. Or, if a contestant was incorrect on the first choice, he or she will be correct after a switch. Since the probability of being incorrect on the first choice is 0.667, then the probability of being correct after a switch is 0.6667.