Question 1

A random variable X is distributed binomially with n = 8 and π = 0.70.The standard deviation of the variable X is approximately

Accepted Answer

A) 0.458 
B) 2.828 
C) 1.680 
D) 1.296 
A) 0.458 
B) 2.828 
C) 1.680 
D) 1.296

Question 2

Based on experience,60 percent of the women who request a pregnancy test at a certain clinic are actually pregnant.In a random sample of 12 women,what is the probability that at least 10 are pregnant?

Accepted Answer

A) 0.0639 
B) 0.1424 
C) 0.0196 
D) 0.0835 
A) 0.0639 
B) 0.1424 
C) 0.0196 
D) 0.0835

Question 3

Which is not a discrete random variable?

Accepted Answer

A) The number of defects in a 4 × 8 sheet of plywood 
B) The number of female passengers who board a plane 
C) The time until failure of a vehicle headlamp 
D) The number of correct answers on a statistics exam 
A) The number of defects in a 4 × 8 sheet of plywood 
B) The number of female passengers who board a plane 
C) The time until failure of a vehicle headlamp 
D) The number of correct answers on a statistics exam

Question 4

Which statement is incorrect?

Accepted Answer

A) The Poisson distribution is always skewed right. 
B) The binomial distribution may be skewed left or right. 
C) The discrete uniform distribution is always symmetric. 
D) The hypergeometric distribution is symmetric. 
A) The Poisson distribution is always skewed right. 
B) The binomial distribution may be skewed left or right. 
C) The discrete uniform distribution is always symmetric. 
D) The hypergeometric distribution is symmetric.

Question 5

The discrete random variable X is the number of students that show up for Professor Smith's office hours on Monday afternoons.The table below shows the probability distribution for X.What is the probability that fewer than 2 students come to office hours on any given Monday?

Accepted Answer

A) 0.10 
B) 0.40 
C) 0.70 
D) 0.90 
A) 0.10 
B) 0.40 
C) 0.70 
D) 0.90

Question 6

On a randomly chosen Wednesday,which probability model would you use to describe the number of convenience store robberies in Los Angeles?

Accepted Answer

A) Binomial 
B) Poisson 
C) Hypergeometric 
D) Uniform 
A) Binomial 
B) Poisson 
C) Hypergeometric 
D) Uniform

Question 7

The expected value (mean)of a binomial variable is 15.The number of trials is 20.The probability of "success" is

Accepted Answer

A) 0.25 
B) 0.50 
C) 0.75 
D) 0.30 
A) 0.25 
B) 0.50 
C) 0.75 
D) 0.30

Question 8

An example of a binomial random variable is the number of pine trees with pine beetle infestation in a random sample of 15 pine trees in Colorado.

Accepted Answer

A) True 
 B)False

Question 9

The hypergeometric distribution is skewed right.

Accepted Answer

A) True 
 B)False

Question 10

A clinic employs nine physicians.Five of the physicians are female.Four patients arrive at once.Assuming the doctors are assigned randomly to patients,what is the probability that all of the assigned physicians are female?

Accepted Answer

A) 0.0397 
B) 0.0295 
C) 0.0808 
D) 0.0533 
A) 0.0397 
B) 0.0295 
C) 0.0808 
D) 0.0533

Question 11

Jankord Jewelers permits the return of their diamond wedding rings,provided the return occurs within two weeks.Typically,10 percent are returned.If eight rings are sold today,what is the probability that fewer than three will be returned?

Accepted Answer

A) 0.9950 
B) 0.9619 
C) 0.0331 
D) 0.1488 
A) 0.9950 
B) 0.9619 
C) 0.0331 
D) 0.1488

A random variable X is distributed binomially with n = 8 and π = 0.70.The standard deviation of the variable X is approximately

Based on experience,60 percent of the women who request a pregnancy test at a certain clinic are actually pregnant.In a random sample of 12 women,what is the probability that at least 10 are pregnant?

Which is not a discrete random variable?

Which statement is incorrect?

The discrete random variable X is the number of students that show up for Professor Smith's office hours on Monday afternoons.The table below shows the probability distribution for X.What is the probability that fewer than 2 students come to office hours on any given Monday?

On a randomly chosen Wednesday,which probability model would you use to describe the number of convenience store robberies in Los Angeles?

The expected value (mean)of a binomial variable is 15.The number of trials is 20.The probability of "success" is

An example of a binomial random variable is the number of pine trees with pine beetle infestation in a random sample of 15 pine trees in Colorado.

The hypergeometric distribution is skewed right.

A clinic employs nine physicians.Five of the physicians are female.Four patients arrive at once.Assuming the doctors are assigned randomly to patients,what is the probability that all of the assigned physicians are female?

Jankord Jewelers permits the return of their diamond wedding rings,provided the return occurs within two weeks.Typically,10 percent are returned.If eight rings are sold today,what is the probability that fewer than three will be returned?

Overview of Statistics

Data Collection

Describing Data Visually

Descriptive Statistics

Probability

Continuous Probability Distributions

Sampling Distributions and Estimation

One-Sample Hypothesis Tests

Two-Sample Hypothesis Tests

Analysis of Variance

Simple Regression

Multiple Regression

Chi-Square Tests

Filters

Exam 6: Discrete Probability Distributions

A random variable X is distributed binomially with n = 8 and π = 0.70.The standard deviation of the variable X is approximately

Based on experience,60 percent of the women who request a pregnancy test at a certain clinic are actually pregnant.In a random sample of 12 women,what is the probability that at least 10 are pregnant?

Which is not a discrete random variable?

Which statement is incorrect?

The discrete random variable X is the number of students that show up for Professor Smith's office hours on Monday afternoons.The table below shows the probability distribution for X.What is the probability that fewer than 2 students come to office hours on any given Monday?

On a randomly chosen Wednesday,which probability model would you use to describe the number of convenience store robberies in Los Angeles?

The expected value (mean)of a binomial variable is 15.The number of trials is 20.The probability of "success" is

An example of a binomial random variable is the number of pine trees with pine beetle infestation in a random sample of 15 pine trees in Colorado.

The hypergeometric distribution is skewed right.

A clinic employs nine physicians.Five of the physicians are female.Four patients arrive at once.Assuming the doctors are assigned randomly to patients,what is the probability that all of the assigned physicians are female?

Jankord Jewelers permits the return of their diamond wedding rings,provided the return occurs within two weeks.Typically,10 percent are returned.If eight rings are sold today,what is the probability that fewer than three will be returned?

Overview of Statistics

Data Collection

Describing Data Visually

Descriptive Statistics

Probability

Continuous Probability Distributions

Sampling Distributions and Estimation

One-Sample Hypothesis Tests

Two-Sample Hypothesis Tests

Analysis of Variance

Simple Regression

Multiple Regression

Chi-Square Tests

Filters