Probability Test Worksheets With Answers (Page 6 of 9) in pdf

Probability Test Worksheets With Answers Page 6

d. what is the probability that the team played during the day given that they lost?

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e. what is the probability that the team had won that game given that they played during the day?

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f. Are the events “Played during the day” and “Won the game” independent? Explain using the

probabilities in parts (a) and (e).

Since the probabilities in parts (a) and (e) are not equal, these two events are not independent.

16. (4 points) The probability that a statistics student reads the textbook is 0.65. The probability

a student does the homework is 0.75. The probability that a student reads the book and does

the homework is 0.51.

If a student is randomly selected, what is the probability that the student reads the book or does the

homework?

P(A or B) = P(A) + P(B) – P(A and B) = 0.65 + 0.75 – 0.51 = 0.89

17. (6 points) A printing company’s bookbinding machine has a probability of 0.021 of

producing a defective book. This machine is used to bind three books.

a. Find the probability that all three books are defective.

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(0.021)(0.021)(0.021) = 9.261 ×10

b. Find the probability that none of the three books are defective.

(1 – 0.021)(1 – 0.021)(1 – 0.021) = 0.9383

18. (6 points) A sociologist surveyed the households in a small town. The random variable

represents the number of dependent children per household.

P(X)

0.07

0.20

0.38

0.13

a. Find the missing probability value.

Since the probabilities must add up to 1, the missing value must be 0.22.

b. What is the probability that a randomly selected household has 3 or more dependent children?

3 or 4 children: 0.22 + 0.13 = 0.35

Probability Test Worksheets With Answers Page 6