Question 1

Assume z is a standard normal random variable. Then P(1.20 ≤ z ≤ 1.85) equals _____.

Accepted Answer

A)  .4678 
B)  .3849 
C)  .8527 
D)  .0829

Question 2

For the standard normal probability distribution, the area to the left of the mean is _____.

Accepted Answer

A)  -.5 
B)  0.5 
C)  any value between 0 and 1 
D)  1

Question 3

A uniform probability distribution is a continuous probability distribution where the probability that the random variable assumes a value in any interval of equal length is _____.

Accepted Answer

A)  different for each interval 
B)  the same for each interval 
C)  either different or the same depending on the magnitude of the standard deviation 
D)  None of the answers is correct.

Question 4

For a standard normal distribution, the probability of obtaining a z value between -1.9 and 1.7 is _____.

Accepted Answer

A)  .9267 
B)  .4267 
C)  1.4267 
D)  .5000

Question 5

The mean of a standard normal probability distribution _____.

Accepted Answer

A)  is always equal to 1 
B)  can be any value as long as it is positive 
C)  can be any value 
D)  None of the answers is correct.

Question 6

Excel's NORM.S.INV function can be used to compute _____.

Accepted Answer

A)  cumulative probabilities for a standard normal z value 
B)  the standard normal z value given a cumulative probability 
C)  cumulative probabilities for a normally distributed x value 
D)  the normally distributed x value given a cumulative probability

Question 7

The assembly time for a product is uniformly distributed between 6 and 10 minutes. The standard deviation of assembly time (in minutes) is approximately _____.

Accepted Answer

A)  .33 
B)  .13 
C)  16 
D)  None of the answers is correct.

Question 8

There is a lower limit but no upper limit for a random variable that follows the _____ probability distribution.

Accepted Answer

A)  uniform 
B)  normal 
C)  exponential 
D)  binomial

Question 9

The ages of students at a university are normally distributed with a mean of 21. What percentage of the student body is at least 21 years old?

Accepted Answer

A)  It could be any value, depending on the magnitude of the standard deviation. 
B)  50% 
C)  21% 
D)  1.96%

Question 10

The assembly time for a product is uniformly distributed between 6 and 10 minutes. The probability density function has what value in the interval between 6 and 10?

Accepted Answer

A)  .25 
B)  4.00 
C)  5.00 
D)  0

Question 11

For a uniform probability density function, the height of the function _____.

Accepted Answer

A)  cannot be larger than1 
B)  is the same for each value of x 
C)  is different for various values of x 
D)  decreases as x increases

Question 12

In a standard normal distribution, the range of values of z is from _____.

Accepted Answer

A)  minus infinity to infinity 
B)  -1 to 1 
C)  0 to 1 
D)  -3.09 to 3.09

Question 13

The assembly time for a product is uniformly distributed between 6 and 10 minutes. The expected assembly time (in minutes) is _____.

Accepted Answer

A)  16 
B)  2 
C)  8 
D)  4

Question 14

Assume z is a standard normal random variable. Then P(z ≥ 2.11) equals _____.

Accepted Answer

A)  .4821 
B)  .9821 
C)  .5 
D)  .0174

Question 15

Assume z is a standard normal random variable. Then P(-1.20 ≤ z ≤ 1.50) equals _____.

Accepted Answer

A)  .0483 
B)  .3849 
C)  .4332 
D)  .8181

Question 16

Assume z is a standard normal random variable. Then P(-1.5 ≤ z ≤ 1.09) equals _____.

Accepted Answer

A)  .4322 
B)  .3621 
C)  .7953 
D)  .0711

Question 17

Excel's EXPON.DIST function has how many inputs?

Accepted Answer

A)  2 
B)  3 
C)  4 
D)  5

Question 18

Assume z is a standard normal random variable. Then P(-1.96 ≤ z ≤ -1.4) equals _____.

Accepted Answer

A)  .8942 
B)  .0558 
C)  .475 
D)  .4192

Question 19

The mean, median, and mode have the same value for which of the following probability distributions?

Accepted Answer

A)  uniform 
B)  normal 
C)  exponential 
D)  Poisson

Question 20

The average starting salary of this year's MBA students is $35,000 with a standard deviation of $5,000. Furthermore, it is known that the starting salaries are normally distributed. What are the minimum and maximum starting salaries of the middle 95% of MBA graduates?

Accepted Answer

The answer of The average starting salary of this year's...

Exam 6: Continuous Probability Distributions