1. Quiz 4  Probability Distributions

2. 1. In families of three children what is the mean number of girls (assuming P(girl)=0.500)? a) 1 b) 1.5 c) 2 d) 2.5

3. 2. What is the expected return on 1 lottery ticket from a lottery with 1000 tickets each costing $2 with 1 winning prize of $1000? a) –$2 b) $0 c) $2 d) –$1

4. 3. What is the expected return on 1 lottery ticket from a lottery with 1000 tickets each costing $2 with 1 winning prize of $1000 & two 2 nd prizes of $500? a) -$2 b) $0 c) $1 d) $2

5. 4. Compute 8 C 2 ? a) 8 b) 28 c) 56 d) 112

6. 5. Which condition is not necessary for a binomial distribution? a) Two outcomes per trial. b) Trials are independent of each other. c) Has a fixed number of trial. d) Probability changes from trial to trial.

7. 6. What is the probability of getting 50% (or 3/6) on a T/F quiz of 6 questions by guessing? a) 50% b) 31% c) 25% d) 10%

8. 7. What is the probability of passing a 5-choice quiz of four questions by guessing? a) 5% b) 10% c) 18% d) 25%

9. 8. What is the probability of getting at least one head when flipping a coin three times? a) 7/8 b) 3/4 c) 1/2 d) 1/8