APU MATH 302 MIDTERM EXAM

Part 1 of 9 -  1.0/ 1.0 Points

Question 1 of 25 1.0/ 1.0 Points
Which measure of central location is meaningful when the data are categorical?

   A.The mode

  B.The median

  C.The mean

  D.The range

Answer Key: A

Part 2 of 9 -  2.0/ 2.0 Points

Question 2 of 25 1.0/ 1.0 Points
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

Answer Key: D

Question 3 of 25 1.0/ 1.0 Points
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

Answer Key: D

Part 3 of 9 -  3.0/ 3.0 Points

Question 4 of 25 1.0/ 1.0 Points
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

Answer Key: D

Question 5 of 25 1.0/ 1.0 Points
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

Answer Key: B

Question 6 of 25 1.0/ 1.0 Points
Which term is NOT synonymous with the expected value of a discrete probability distribution?

  A.mean

   B.variance

  C.theoretical average

  D.μ

Answer Key: B

Part 4 of 9 -  5.0/ 6.0 Points

Question 7 of 25 1.0/ 1.0 Points
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

Answer Key: D

Question 8 of 25 1.0/ 1.0 Points
The continuous distribution characterized by a symmetric, bell-shaped curve is the:

  A.binomial distribution

  B.Poisson distribution

  C.exponential distribution 
   D.normal distribution

Answer Key: D

Question 9 of 25 0.0/ 1.0 Points
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

Answer Key: D

Question 10 of 25 1.0/ 1.0 Points
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

Answer Key: D

Question 11 of 25 1.0/ 1.0 Points
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

Answer Key: C

Question 12 of 25 1.0/ 1.0 Points
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 

Answer Key: B