Psych 302

David J. Weiss

Probability Problem Set 1

1. If we roll two dice, what is the probability of not obtaining an even sum?
2. If we roll four dice, what is the probability that none of them will show a "four"?
3. Two cards will be dealt from a well-shuffled deck. You may choose from one of two options: (a) If the first card is a club, you win $1; (b) If the first card is a club or the second card is a diamond (or both), you win $1. Which option is better, or are they equivalent?
4. You and two friends go to the stable for horseback riding. There are four horses available. One of these horses is a wild, violent animal named Hitler. Assume that you and your friends will be assigned to horses randomly. What is the probability that (a) you will have to ride Hitler; (b) one of your group will have to ride Hitler? What is the probability that you will suffer serious injury?
5. Three dice are rolled. What is the chance of getting a sum of three? What is the chance that all three dice show three or more spots?
6. If you are dealt four cards from a well-shuffled deck, what is the probability that you will receive exactly three kings?

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