Quiz 4

Probability Distributions

1. In families of three children what is the mean number of girls (assuming P(girl)=0.500)?

a) 1b) 1.5c) 2d) 2.5

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) –$2b) $0c) $2d) –$1

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 2nd prizes of $500?

a) -$2b) $0c) $1d) $2

4. Compute 8C2?

a) 8b) 28c) 56d) 112

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.

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%

7. What is the probability of passing a 5-choice quiz of four questions by guessing?

a) 5%b) 10%c) 18%d) 25%

8. What is the probability of getting at least one head when flipping a coin three times?

a) 7/8b) 3/4c) 1/2d) 1/8