1. If P(A) = 0.24 and P(B) = 0.52 and events A and B are independent, what is P(A or B)?
E) The answer cannot be determined from the information given. C)

2. 2. Which of the following pairs of events, A and B, are disjoint (mutually exclusive)?
A  the odd numbers; B  the number 5
B) A  the even numbers; B  the numbers greater than 10
C) A  the numbers less than 5; B  all negative numbers
E) A  negative numbers; B  odd numbers
D) A  the numbers above 100; B  the numbers less than -200

3. 3) Shameel has a flight to catch on Monday morning
3) Shameel has a flight to catch on Monday morning. His father will give him a ride to the airport. If it rains, the traffic will be bad and the probability that he will miss his flight is If it doesn't rain, the probability that he will miss his flight is The probability that it will rain on Monday is
Suppose that Shameel misses his flight. What is the probability that it was raining?
C) 1.098
D) E) 0.18
B) 0.523

4. Some employers use lie detector tests to screen job applicants
Some employers use lie detector tests to screen job applicants. Lie detector tests are not completely reliable. Suppose that a polygraph can detect 65% of lies, but incorrectly identifies 16% of true statements as lies.
A company gives its job applicants a polygraph test, asking "Did you tell the truth on your job application?". All the applicants answer "Yes", but the test identifies some of those answers as lies, thereby causing the person to fail the test.
Suppose that 90% of the job applicants tell the truth during the polygraph test. What is the probability that a person who fails the test was actually telling the truth?
B) 0.16
D) E) 0.9
C) 0.689

5. 5) You pick a card from a deck. If you get a club, you win $90
5) You pick a card from a deck. If you get a club, you win $90. If not, you get to draw again (after replacing the first card). If you get a club the second time, you win $30. If not, you lose.
Find the expected amount you will win.
$ B) $ C) $36.56
D) $45.00
E) $28.13

6. 6) Sue Anne owns a medium-sized business
6) Sue Anne owns a medium-sized business. The probability model below describes the number of employees that may call in sick on any given day.
What is the standard deviation of the number of employees calling in sick each day?
Number of sick employees 1 2 3 4
P(X=x)
0.05
0.4
0.25
0.2
0.1
C) 0.98
D) E) 1.20
B) 1.09

7. 7) A company sells light bulbs in packages of 20 and estimates that the mean number of defective light bulbs in a package is 0.5 with a standard deviation of If a customer buys 12 packages, what are the expected value and standard deviation of the number of defective light bulbs? Assume that packages are independent of each other.
A) μ = 6, σ = 2.42
B) μ = 1.73, σ = 2.42
D) μ = 6, σ = 8.4
C) μ = 6, σ =
E) μ = 1.73, σ = 8.4

8. Mean SD X 110 15 Y 150 A) μ = 180, σ = 47.43 B) μ = 180, σ = 42.43
8) Given independent random variables with means and standard deviations as shown, find the mean and standard deviation of the variable 3X - Y .
Mean SD X
110 15 Y
150
A) μ = 180, σ =
B) μ = 180, σ =
C) μ = 180, σ = 30
D) μ = 480, σ =
E) μ = -120, σ = 30

9. 9) You pick a card from a deck. If you get a face card, you win $15
9) You pick a card from a deck. If you get a face card, you win $15. If you get an ace, you win $25 plus an extra $40 for the ace of hearts. For any other card you win nothing.
Create a probability model for the amount you win at this game.

10. C 2) D
B 4) C
E 6) B
7) A 8) A
Review – Multiple Choice
Chapters 14, 15 and 16