Question 1

The annual income for a sample of 500 part-time students is normally distributed with a mean income of $30,000 and a standard deviation of $3,000. The income range that separates the top 25% from the lower 75% is __________.

Accepted Answer

The answer of The annual income for a sample of...

Question 2

For a uniformly distributed random variable, x, P(x) is constant.

Accepted Answer

A) True 
 B)False

Question 3

Suppose a tire manufacturer wants to set a mileage guarantee on its new XB 70 tire. Tests revealed that the tire's mileage is normally distributed with a mean of 47,900 miles and a standard deviation of 2,050 miles. The manufacturer wants to set the guaranteed mileage so that no more than 5% of the tires will have to be replaced. What guaranteed mileage should the manufacturer announce?

Accepted Answer

A)  44,518 
B)  32,960 
C)  49,621 
D)  40,922

Question 4

Describe the uniform distribution.

Accepted Answer

The answer of Describe the uniform distribution....

Question 5

What is the area under the normal curve between z = 0.0 and z = 1.79?

Accepted Answer

A)  0.4633 
B)  0.0367 
C)  0.9599 
D)  0.0401

Question 6

A major credit card company has determined that customers charge between $100 and $1100 per month. If the monthly amount charged is uniformly distributed, the standard deviation of the monthly amount charged would be ________.

Accepted Answer

The answer of A major credit card company has determined...

Question 7

The total area of a normal probability distribution is _______.

Accepted Answer

A)  Between -3.0 and 3.0 
B)  1.00 
C)  Dependent on a value of "z" 
D)  Approximated by the binomial distribution

Question 8

Which of the following is true in a normal distribution?

Accepted Answer

A)  The mean equals zero. 
B)  The mode and the third quartile are equal. 
C)  The mean divides the distribution into two equal areas. 
D)  The area under the curve is 0.68.

Question 9

The mean amount spent by a family of four on food is $500 per month with a standard deviation of $75. Assuming that the food costs are normally distributed, what is the probability that a family spends less than $410 per month?

Accepted Answer

A)  0.2158 
B)  0.8750 
C)  0.0362 
D)  0.1151

Question 10

A large manufacturing firm tests job applicants. Test scores are normally distributed with a mean of 500 and a standard deviation of 50. Management is considering placing a new hire in an upper-level management position if the person scores in the upper sixth percent of the distribution. What is the lowest score a new hire must earn to qualify for a responsible position?

Accepted Answer

A)  50 
B)  625 
C)  460 
D)  578

Question 11

The weight of a bag of corn chips is normally distributed with a mean of 22 ounces and a standard deviation of 0.5 ounces. The probability that a bag of corn chips weighs more than 23 ounces is ____.

Accepted Answer

The answer of The weight of a bag of corn...

Question 12

The mean of any uniform probability distribution is _________.

Accepted Answer

A)  (b - a)/2 
B)  (a + b)/2 
C)   
D)  nπ

Question 13

What happens to the shape of a binomial distribution as the number of trials increases?

Accepted Answer

The answer of What happens to the shape of a...

Question 14

The proportion of the area under a normal curve that is to the left of z = 0.50 is _______.

Accepted Answer

The answer of The proportion of the area under a...

Question 15

The expected value of a uniform distribution is computed using the formula _________.

Accepted Answer

The answer of The expected value of a uniform distribution...

Question 16

The time to fly between New York City and Chicago is uniformly distributed with a minimum of 120 minutes and a maximum of 150 minutes. What is the distribution's mean?

Accepted Answer

A)  120 minutes 
B)  150 minutes 
C)  135 minutes 
D)  270 minutes

Question 17

Two normal distributions are compared. One has a mean of 10 and a standard deviation of 10. The second normal distribution has a mean of 10 and a standard deviation of 2. Which of the following is true?

Accepted Answer

A)  The locations of the distributions are different. 
B)  The distributions are from two different families of distributions. 
C)  The dispersions of the distributions are different. 
D)  The dispersions of the distributions are the same.

Question 18

For the exponential distribution, the mean and standard deviation are equal.

Accepted Answer

A) True 
 B)False

Question 19

A binomial distribution has 50 trials (n = 50) with a probability of success of 0.50 (π = 0.50). To use the normal distribution to approximate the binomial, what are the mean and standard deviation?

Accepted Answer

A)  µ = 25 and σ = 3.5355 
B)  µ = 25 and σ = 12.5 
C)  µ = 25 and σ = 4.33 
D)  µ = 50 and σ = 100

Question 20

A major credit card company has determined that customers charge between $100 and $1,100 per month. If the average monthly amount charged is uniformly distributed, the percent of monthly changes between $311 and $889 is _______.

Accepted Answer

The answer of A major credit card company has determined...

Exam 7: Continuous Probability Distributions

The annual income for a sample of 500 part-time students is normally distributed with a mean income of $30,000 and a standard deviation of $3,000. The income range that separates the top 25% from the lower 75% is __________.

For a uniformly distributed random variable, x, P(x) is constant.

Describe the uniform distribution.

What is the area under the normal curve between z = 0.0 and z = 1.79?

A major credit card company has determined that customers charge between $100 and $1100 per month. If the monthly amount charged is uniformly distributed, the standard deviation of the monthly amount charged would be ________.

The total area of a normal probability distribution is _______.

Which of the following is true in a normal distribution?

The mean amount spent by a family of four on food is $500 per month with a standard deviation of $75. Assuming that the food costs are normally distributed, what is the probability that a family spends less than $410 per month?

The weight of a bag of corn chips is normally distributed with a mean of 22 ounces and a standard deviation of 0.5 ounces. The probability that a bag of corn chips weighs more than 23 ounces is ____.

The mean of any uniform probability distribution is _________.

What happens to the shape of a binomial distribution as the number of trials increases?

The proportion of the area under a normal curve that is to the left of z = 0.50 is _______.

The expected value of a uniform distribution is computed using the formula _________.

The time to fly between New York City and Chicago is uniformly distributed with a minimum of 120 minutes and a maximum of 150 minutes. What is the distribution's mean?

Two normal distributions are compared. One has a mean of 10 and a standard deviation of 10. The second normal distribution has a mean of 10 and a standard deviation of 2. Which of the following is true?

For the exponential distribution, the mean and standard deviation are equal.

A binomial distribution has 50 trials (n = 50) with a probability of success of 0.50 (π = 0.50) . To use the normal distribution to approximate the binomial, what are the mean and standard deviation?

A major credit card company has determined that customers charge between $100 and $1,100 per month. If the average monthly amount charged is uniformly distributed, the percent of monthly changes between $311 and $889 is _______.