Question 1

The weight of football players is normally distributed with a mean of 200 pounds and a standard deviation of 25 pounds. The probability of a player weighing more than 250 pounds is

Accepted Answer

A)   0.228.
B)   0.9772.
C)   0.0022.
D)   0.9978. A

Question 2

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. A

Question 3

For a normal distribution, a negative value of z indicates

Accepted Answer

A)   a mistake has been made in computations, because z is always positive.
B)   the area corresponding to the z is negative.
C)   the z is to the left of the mean.
D)   the z is to the right of the mean. C

Question 4

A professor at a local university noted that the exam grades of her students were normally distributed with a mean of 73 and a standard deviation of 11. Students who made 59.99 or lower on the exam failed the course. What percent of students failed the course?

Accepted Answer

A)   11.85%
B)   88.15%
C)   1.80%
D)   98.20%

Question 5

A manufacturing process produces items whose weights are normally distributed. It is known that 22.57% of all the items produced weigh between 100 grams up to the mean and 49.18% weigh from the mean up to 190 grams. Determine the mean and the standard deviation.

Accepted Answer

The answer of A manufacturing process produces items whose weights...

Question 6

The probability that a continuous random variable takes any specific value

Accepted Answer

A)   is equal to zero.
B)   is at least 0.5.
C)   depends on the probability density function.
D)   is very close to 1.0.

Question 7

Given that z is a standard normal random variable, what is the probability that z  -2.12?

Accepted Answer

A)   0.4830
B)   0.9830
C)   0.017
D)   0.966

Question 8

The average starting salary of this year's MBA students is $45,000 with a standard deviation of $5,000. Furthermore, it is known that the starting salaries are normally distributed. What are the minimum and the maximum starting salaries of the middle 95% of MBA graduates?

Accepted Answer

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

Question 9

The function that defines the probability distribution of a continuous random variable is a

Accepted Answer

A)   normal function.
B)   uniform function.
C)   either normal of uniform depending on the situation.
D)   probability density function.

Question 10

The area of the continuous uniform probability distribution is​

Accepted Answer

A)   ​triangular.
B)   ​rectangular.
C)   ​bell-shaped.
D)   ​a series of vertical lines.

Question 11

The random variable x is known to be uniformly distributed between 70 and 100. The probability of x having a value between 80 to 95 is

Accepted Answer

A)   0.75.
B)   0.5.
C)   0.05.
D)   1.

Question 12

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 13

z is a standard normal random variable. The P (1.20  z  2.10) equals

Accepted Answer

A)   0.7618.
B)   0.2382.
C)   0.9028.
D)   0.0972.

Question 14

Given that z is a standard normal random variable, what is the value of z if the area to the right of z is 0.1801?

Accepted Answer

A)   0.91
B)   -0.91
C)   0.09
D)   -0.09

Question 15

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

Accepted Answer

A)   1.3333.
B)   1.1547.
C)   0.1111.
D)   0.5773.

Question 16

A continuous random variable is uniformly distributed between a and b. The probability density function between a and b is

Accepted Answer

A)   zero.
B)   (a - b) .
C)   (b - a) .
D)   1/(b - a) .

Question 17

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 18

Which of the following are continuous random variables?​ 
I. The weight of an elephant
II. The time to answer a questionnaire
III. The number of floors in a skyscraper
IV. The square feet of countertop in a kitchen

Accepted Answer

A)   ​I and II only
B)   ​III and IV only
C)   ​I, II and IV only​
D)   ​I, II, II, and IV

Question 19

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 20

z is a standard normal random variable. The P(z ≥ 2.11) equals

Accepted Answer

A)   0.4821.
B)   0.9821.
C)   0.5.
D)   0.0174.

Exam 6: Continuous Probability Distributions

The weight of football players is normally distributed with a mean of 200 pounds and a standard deviation of 25 pounds. The probability of a player weighing more than 250 pounds is

The uniform, normal, and exponential distributions

For a normal distribution, a negative value of z indicates

A professor at a local university noted that the exam grades of her students were normally distributed with a mean of 73 and a standard deviation of 11. Students who made 59.99 or lower on the exam failed the course. What percent of students failed the course?

A manufacturing process produces items whose weights are normally distributed. It is known that 22.57% of all the items produced weigh between 100 grams up to the mean and 49.18% weigh from the mean up to 190 grams. Determine the mean and the standard deviation.

The probability that a continuous random variable takes any specific value

Given that z is a standard normal random variable, what is the probability that z -2.12?

The average starting salary of this year's MBA students is $45,000 with a standard deviation of $5,000. Furthermore, it is known that the starting salaries are normally distributed. What are the minimum and the maximum starting salaries of the middle 95% of MBA graduates?

The function that defines the probability distribution of a continuous random variable is a

The area of the continuous uniform probability distribution is

The random variable x is known to be uniformly distributed between 70 and 100. The probability of x having a value between 80 to 95 is

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

z is a standard normal random variable. The P (1.20 z 2.10) equals

Given that z is a standard normal random variable, what is the value of z if the area to the right of z is 0.1801?

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

A continuous random variable is uniformly distributed between a and b. The probability density function between a and b is

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?

Which of the following are continuous random variables? I. The weight of an elephant II. The time to answer a questionnaire III. The number of floors in a skyscraper IV. The square feet of countertop in a kitchen

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

z is a standard normal random variable. The P(z ≥ 2.11) equals

Exam 6: Continuous Probability Distributions

The weight of football players is normally distributed with a mean of 200 pounds and a standard deviation of 25 pounds. The probability of a player weighing more than 250 pounds is

The uniform, normal, and exponential distributions

For a normal distribution, a negative value of z indicates

A professor at a local university noted that the exam grades of her students were normally distributed with a mean of 73 and a standard deviation of 11. Students who made 59.99 or lower on the exam failed the course. What percent of students failed the course?

A manufacturing process produces items whose weights are normally distributed. It is known that 22.57% of all the items produced weigh between 100 grams up to the mean and 49.18% weigh from the mean up to 190 grams. Determine the mean and the standard deviation.

The probability that a continuous random variable takes any specific value

Given that z is a standard normal random variable, what is the probability that z -2.12?

The average starting salary of this year's MBA students is $45,000 with a standard deviation of $5,000. Furthermore, it is known that the starting salaries are normally distributed. What are the minimum and the maximum starting salaries of the middle 95% of MBA graduates?

The function that defines the probability distribution of a continuous random variable is a

The area of the continuous uniform probability distribution is​

The random variable x is known to be uniformly distributed between 70 and 100. The probability of x having a value between 80 to 95 is

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

z is a standard normal random variable. The P (1.20 z 2.10) equals

Given that z is a standard normal random variable, what is the value of z if the area to the right of z is 0.1801?

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

A continuous random variable is uniformly distributed between a and b. The probability density function between a and b is

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?

Which of the following are continuous random variables?​ I. The weight of an elephant II. The time to answer a questionnaire III. The number of floors in a skyscraper IV. The square feet of countertop in a kitchen

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

z is a standard normal random variable. The P(z ≥ 2.11) equals

The area of the continuous uniform probability distribution is

Which of the following are continuous random variables? I. The weight of an elephant II. The time to answer a questionnaire III. The number of floors in a skyscraper IV. The square feet of countertop in a kitchen