Probabilities 1

(Note: Express your final answer using four decimal places if needed)

1. If a marble is randomly chosen from a bag that contains exactly 12 red marbles, 5 blue marbles, and 3 white marbles, what is the probability that the marble:

a) Will be red?

1. b) Will be blue?

1. c) Will be white?

1. d) Will not be red?

1. e) Will be red or white?

2. Suppose that P(A) = 1/5, P(B) = 4/5, and P(A or B ) = 1/3. Are A and B disjoint events? What is the value of (|)?

3. Suppose that P(A) = 0.29, P(B) = 0.43, and P(A or B ) = 0.72. Are A and B disjoint events? What is the value of (|)?

4. Which of the following values are NOT valid probability values:

a) 0.0003 b) - 0.3 c) 64/66 d) 9/8 e) 2.6/2.59

5. I have 8 books, 5 of which are good. If 3 books are randomly selected, what's the probability that the first is not good, the second is good, and the third is not good?

a) With replacement.

b) Without replacement.

6. If you make random guesses for 7 multiple-choice test questions (each with four possible answers), what is the probability of getting at least 1 correct answer?

7. Suppose that the probability of correct functionality of an alarm clock is 0.64. What is the probability that at least one of 10 alarm clocks will function correctly?

8. Out of 100 people which are either tall or fat or both, 62 are tall, and 55 are fat. If I select one random person out of the 100 what is the probability, he is both tall and fat