MGF 1107

HOMEWORK/ PROBABILITY

1. What is the probability of an event that is:

a) certain to occur?

b) impossible?

c) just as likely to happen as not happen?

d) four times more likely to happen than not happen?

e) half as likely to happen as not happen?

2. If the probability that an event occurs is 5/7, what is the probability that it doesn’t occur?

3. There are four possible outcomes to an experiment. The probabilities of three of them are 1/10, 1/5 and 1/2. What is the probability of the other outcome?

4. Past statistics show that Phil votes Democratic 70% of the time and Republican 30% of the time. Janie votes Republican 75% of the time and Democratic 25% of the time. What is the probability that:

a) Phil votes Republican and Janie votes Republican?

b) Phil votes Republican and Janie votes Democratic?

c) Phil votes Democratic and Janie votes Republican?

d) Phil votes Democratic and Janie votes Democratic?

5. The mayor knows that when he throws a fund-raising party he will take in $5000 30% of the time, $7000 20% of the time, and $4000 50% of the time. If he throws a fund-raising party, how much should he expect to raise?

6. A candidate knows from polling that 60% of Hispanics favor him, 40% of Anglos favor him, and 10% of blacks favor him. If the Election Day turnout was 50% Hispanic, 30% Anglo, and 20% black, what percentage of the vote should he expect to get?

7. The probability that a registered voter is male is 0.5. The probability that a registered voter is a Democrat is 0.45. What is the probability that a registered voter is a male and not a Democrat?

Answers:

1a) 1 b) 0  c) 1/2 d) 0.8 1e) 1/3

2) 2/7

3) 0.2

4a) 0.225 b) 0.075 c) 0.525 d) 0.175

5) $4900

6) 44%

7) .275