Question 1

For any continuous random variable, the probability that the random variable takes on exactly a specific value is

Accepted Answer

A)  1.00 
B)  0.50 
C)  any value between 0 to 1 
D)  0

Question 2

The life expectancy of a particular brand of tire is normally distributed with a mean of 40,000 and a standard deviation of 5,000 miles.What is the probability that a randomly selected tire will have a life of at least 47,500 miles?

Accepted Answer

A)  0.4332 
B)  0.9332 
C)  0.0668 
D)  0.4993

Question 3

The mean of a standard normal probability distribution

Accepted Answer

A)  is always equal to zero. 
B)  can be any value as long as it is positive. 
C)  can be any value. 
D)  is always greater than zero.

Question 4

The starting salaries of individuals with an MBA degree are normally distributed with a mean of $40,000 and a standard deviation of $5,000.What percentage of MBA's will have starting salaries of $34,000 to $46,000?

Accepted Answer

A)  38.49% 
B)  38.59% 
C)  50% 
D)  76.98%

Question 5

The uniform, normal, and exponential distributions

Accepted Answer

A)  are all continuous probability distributions. 
B)  are all discrete probability distributions. 
C)  can be either continuous or discrete, depending on the data. 
D)  are all the same distributions.

Question 6

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

Accepted Answer

A)  -0.5 
B)  0.5 
C)  any value between 0 to 1 
D)  1

Question 7

The z score for the standard normal distribution

Accepted Answer

A)  is always equal to zero. 
B)  can never be negative. 
C)  can be either negative or positive. 
D)  is always equal to the mean.

Question 8

The probability distribution that can be described by just one parameter is the​

Accepted Answer

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

Question 9

z is a standard normal random variable.The P(-1.5 < z < 1.09) equals

Accepted Answer

A)  0.4322 
B)  0.3621 
C)  0.7953 
D)  0.0711

Question 10

Consider a binomial probability experiment with n = 3 and p = 0.1.Then, the probability of x = 0 is

Accepted Answer

A)  0 
B)  0.0001 
C)  0.001 
D)  0.729

Question 11

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

Accepted Answer

A)  0.9267 
B)  0.4267 
C)  1.4267 
D)  0.5000

Question 12

The time it takes to travel from home to the office is normally distributed with μ = 25 minutes and σ = 5 minutes.What is the probability the trip takes more than 40 minutes?​

Accepted Answer

A)  ​.0013 
B)  ​.0130 
C)  ​.9987 
D)  ​.9990

Question 13

The life expectancy of a particular brand of tire is normally distributed with a mean of 40,000 and a standard deviation of 5,000 miles.What is the probability that a randomly selected tire will have a life of exactly 47,500 miles?

Accepted Answer

A)  0.0000 
B)  0.9332 
C)  0.0668 
D)  0.4993

Question 14

For a continuous random variable x, the height of the function at x is

Accepted Answer

A)  the probability at a given value of x. 
B)  0.50, since it is the middle value. 
C)  a value less than zero. 
D)  named the probability density function f(x).

Question 15

Given that z is a standard normal random variable, what is the value of z if the area to the left of z is 0.0559?

Accepted Answer

A)  0.4441 
B)  -1.59 
C)  0 
D)  1.50

Question 16

The travel time for a college student traveling between her home and her college is uniformly distributed between 40 and 90 minutes.The probability that she will finish her trip in 80 minutes or less is

Accepted Answer

A)  0.02 
B)  0.8 
C)  0.2 
D)  1.00

Question 17

A negative value of z indicates that

Accepted Answer

A)  the number of standard deviations of an observation is to the right of the mean. 
B)  the number of standard deviations of an observation is to the left of the mean. 
C)  a mistake has been made in computations, since z cannot be negative. 
D)  the data has a negative mean.

Question 18

z is a standard normal random variable.The P(1.05 < z < 2.13) equals

Accepted Answer

A)  0.8365 
B)  0.1303 
C)  0.4834 
D)  0.3531

Question 19

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)  at least one. 
D)  zero.

Question 20

Given that z is a standard normal random variable.What is the value of z if the area to the left of z is 0.9382?

Accepted Answer

A)  1.8 
B)  1.54 
C)  2.1 
D)  1.77

Exam 6: Continuous Probability Distributions