Discrete Math
Exam Review 3Name: ______
1. What happens to a set of data following a normal distribution when the standard deviation is increased?
A. It shifts to the left
B. It shifts to the right
C. It produces a wider range of probable values
D. It produces a more narrow range of probable values
2. What happens to a set of data following a normal distribution when the mean is increased?
A. It shifts to the left
B. It shifts to the right
C. It produces a wider range of probable values
D. It produces a more narrow range of probable values
3. A set of data has a mean of 127 and a standard deviation of 15. What is the z-score of ?
A. B. C. D.
4. What is the area under the normal distribution function between and ?
Z / 0.1 / 0.2 / 0.3 / 0.4 / 0.5 / 0.6 / 0.7 / 0.8 / 0.9 / 1.0Area / 0.04 / 0.08 / 0.12 / 0.16 / 0.19 / 0.23 / 0.26 / 0.29 / 0.32 / 0.34
A. 0.11B. 0.23C. 0.32D. 0.35
5. A video game designer is evaluating a new release and issues a pre-release version to a set of testers. The testers spend an average of 12 minutes to complete the first level, with a standard deviation of 3.5 minutes. Assuming a normal distribution for the data, 84% of players should complete the first level in less than how many minutes?
Z / 0.1 / 0.2 / 0.3 / 0.4 / 0.5 / 0.6 / 0.7 / 0.8 / 0.9 / 1.0Area / 0.04 / 0.08 / 0.12 / 0.16 / 0.19 / 0.23 / 0.26 / 0.29 / 0.32 / 0.34
A. 8.5 minutesB. 13 minutesC. 15.5 minutesD. 19 minutes
1. Which of the following data could be represented by a continuous random variable?
A. The outcome from flipping three coins.
B. The outcome from rolling two number cubes.
C. The finishing times of twenty marathon runners.
D. The number of blue cars in a parking lot.
2. Which of the following data could be represented by a discrete random variable?
A. The heights of twenty players on a basketball team.
B. The outcome from rolling a number cube.
C. The time it takes for a bank teller to wait on a customer.
D. The temperature in a neighborhood park.
X / 0 / 1 / 2 / 3 / 4P(x) / / / / /
3. The following table shows the possible values for a random variable, and the corresponding probabilities that the variable will take on each particular value. What is the expected value of the random variable?
A. 2B. 1.7C. 2.1D. 2.4
X / 2 / 3 / 4 / 5P(x) / 0.27 / 0.23 / 0.12 / 0.38
4. The following table shows the possible values for a random variable, and the corresponding probabilities that the variable will take on each particular value. What is the expected value of the random variable?
A. 3.42B. 4.03C. 2.29D. 3.61
5. A jar contains 1 black and 2 green marbles. Two marbles are drawn from the jar. If X equals the number of black marbles drawn, which of the following tables shows the correct data?
X / 0 / 1P(x) / /
X / 0 / 1
P(x) / /
A. B.
X / 1 / 2P(x) / /
X / 1 / 2
P(x) / /
C. D.
6. A jar contains 2 red, 1 white, and 3 blue marbles. Two marbles are drawn. If X equals the number of red marbles drawn, which of the following tables shows the correct data?
X / 0 / 1 / 2P(x) / / /
X / 1 / 2 / 3
P(x) / / /
A. B.
X / 1 / 2 / 3P(x) / / /
X / 0 / 1 / 2
P(x) / / /
C.D.
7. Which of the following data could be represented by a continuous random variable?
A. The amount of sugar found in an orange selected at random from a crate.
B. The number on which a spinner lands in a board game.
C. The number of defective sets of headphones in a box of fifty.
D. The number of people attending a screening of a new movie.
8. Which of the following data could be represented by a discrete random variable?
A. The weights of players on a football team.
B. The lengths of fish caught in a fishing tournament.
C. The number of children in a family
D. The amount of salt found in a can of tomato soup.
X / 5 / 6 / 7 / 8P(x) / 0.25 / 0.35 / 0.22 / 0.18
9. The following table shows the possible values for a random variable, and the corresponding probabilities that the variable will take on each particular value. What is the expected value of the random variable?
A. 7.23B. 6.82C. 7.09D. 6.33
10. A jar contains 2 yellow and 3 green marbles. Two marbles are drawn. If X equals the number of green marbles drawn, what is the expected value of X?
A. 1B. 2C. 1.5D. 1.2
1. Evaluate when and
A. B. C. D. No solution
2. Evaluate when and
A. B. C. D. No solution
3. Evaluate when and and
A. B. C. D. No solution
4. Evaluate when and and
A. B. C. D. No solution
5. Evaluate when and and
A. B. C. D. No solution
6. Evaluate when and
A. B. C. D. No solution
7. Evaluate when and
A. B. C. D. No solution
8. Evaluate when and
A. B. C. D. No solution
9. Evaluate when and
A. B. C. D. No solution
10. Evaluate when and
A. B. C. D. No solution
11. Evaluate when and
A. B. C. D. No solution
12. Evaluate when
A. No solutionB. C. D.
13. Find the dimensions of
A. No solutionB. C. D.
14. Evaluate when and
A. B. C. D. No solution
15. Evaluate when and
A. B. C. D. No solution
16. Evaluate when
A. B. No solutionC. D.
17. Evaluate when and
A. B. C. D. No solution
18. Evaluate when and
A. B. C. D. No solution
19. Evaluate when and
A. No solution B. C. D.
20. Evaluate when and
A. B. No solutionC. D.