Question 1: Which measure of central location is meaningful when the data are categorical?

A. The mode

B. The median

C. The mean

D. The range

Question 2: What type of probability uses sample spaces to determine the numerical probability that an event will occur?

A. subjective probability

B. empirical probability

C. conditional probability

D. classical probability

Question 3: The formal way to revise probabilities based on new information is to use:

A. common sense probabilities

B. unilateral probabilities

C. complementary probabilities

D. conditional probabilities

Question 4: Suppose that 50 identical batteries are being tested. After 8 hours of continuous use, assume that a given battery is still operating with a probability of 0.70 and has failed with a probability of 0.30. What is the probability that fewer than 40 batteries will last at least 8 hours?

A. 0.0789

B. 0.9598

C. 0.7986

D. 0.9211

Question 5: Find the variance of the following probability distribution.

X P(X)

1 0.20

2 0.15

3 0.25

4 0.25

5 0.15

A. 1.34

B. 1.8

C. 0.48

D. 1.16

Question 6: Which term is NOT synonymous with the expected value of a discrete probability distribution?

A. mean

B. variance

C. theoretical average

D. μ

Question 7: Given that Z is a standard normal random variable, P(-1.0 < Z < 1.5) is

A. 0.8413

B. 0.0919

C. 0.9332

D. 0.7745

Question 8: The continuous distribution characterized by a symmetric, bell-shaped curve is the:

A. binomial distribution

B. Poisson distribution

C. exponential distribution

D. normal distribution

Question 9: The standard deviation of a probability distribution must be:

A. a number between 0 and 1

B. less than the value of the mean

C. a negative number

D. a nonnegative number

Question 10: Given that Z is a standard normal variable, the value z for which P(Z < z) = 0.2580 is

A. -0.70

B. 0.758

C. 0.242

D. -0.65

Question 11: The standard normal distribution has a mean of ___ and standard deviation of ___, respectively.

A. 1 and 1

B. 1 and 0

C. 0 and 1

D. 0 and 0

Question 12: One reason for standardizing random variables is to measure variables with:

A. similar means and standard deviations on two scales

B. different means and standard deviations on a single scale

C. dissimilar means and similar standard deviations in like terms

D. different means and standard deviations on a non-standard scale