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