Question 1

Any normal distribution has a mean of 0 and a standard deviation of 1.

Accepted Answer

A) True 
 B)False

Question 2

Could this function be a PDF?

Accepted Answer

A)  Yes. 
B)  No. 
C)  It depends on x. 
A)  Yes. 
B)  No. 
C)  It depends on x.

Question 3

If arrivals follow a Poisson distribution,waiting times follow the exponential distribution.

Accepted Answer

A) True 
 B)False

Question 4

A multiple choice exam has 100 questions.Each question has five choices.What would be the approximate probability that a "guesser" could achieve a score of 30 or more?

Accepted Answer

A)  0.0088 
B)  0.0062 
C)  0.0015 
D)  0.4913 
A)  0.0088 
B)  0.0062 
C)  0.0015 
D)  0.4913

Question 5

Light bulbs are normally distributed with an average lifetime of 1000 hours and a standard deviation of 250 hours.The probability that a light bulb picked at random will last less than 1500 hours is about:

Accepted Answer

A)  97.72 percent. 
B)  95.44 percent. 
C)  75.00 percent. 
D)  68.00 percent. 
A)  97.72 percent. 
B)  95.44 percent. 
C)  75.00 percent. 
D)  68.00 percent.

Question 6

A triangular distribution can be skewed either left or right.

Accepted Answer

A) True 
 B)False

Question 7

The area under the normal curve between the 20th and 70th percentiles is equal to:

Accepted Answer

A)  0.7000. 
B)  0.5000. 
C)  0.9193.
Logically,this must be .70 - .20 = .50,as you can verify from Appendix C 
A)  0.7000. 
B)  0.5000. 
C)  0.9193.
Logically,this must be .70 - .20 = .50,as you can verify from Appendix C

Question 8

The normal distribution is a good approximation to the binomial if both π ≥ 10 and n ≥ 10.

Accepted Answer

A) True 
 B)False

Question 9

Which is the correct Excel formula for the 80th percentile of a distribution that is N(475,33)?

Accepted Answer

A)  =NORM.DIST(80,475,33,1) 
B)  =NORM.INV(0.80,475,33) 
C)  =NORM.S.INV((80 - 475)/33) 
A)  =NORM.DIST(80,475,33,1) 
B)  =NORM.INV(0.80,475,33) 
C)  =NORM.S.INV((80 - 475)/33)

Question 10

A random variable X is best described by a continuous uniform distribution from 20 to 45 inclusive.The mean of this distribution is:

Accepted Answer

A)  30.5. 
B)  31.5. 
C)  32.5. 
D)  33.5. 
A)  30.5. 
B)  31.5. 
C)  32.5. 
D)  33.5.

Question 11

Which probability model is most appropriate to describe the waiting time (working days)until an office photocopier breaks down (i.e. ,requires unscheduled maintenance)?

Accepted Answer

A)  Normal 
B)  Uniform 
C)  Exponential 
D)  Poisson 
A)  Normal 
B)  Uniform 
C)  Exponential 
D)  Poisson

Question 12

What are the mean and standard deviation for the standard normal distribution?

Accepted Answer

A)  μ = 0,σ = 0 
B)  μ = 1,σ = 1 
C)  μ = 1,σ = 0 
D)  μ = 0,σ = 1 
A)  μ = 0,σ = 0 
B)  μ = 1,σ = 1 
C)  μ = 1,σ = 0 
D)  μ = 0,σ = 1

Any normal distribution has a mean of 0 and a standard deviation of 1.

Could this function be a PDF?

If arrivals follow a Poisson distribution,waiting times follow the exponential distribution.

A multiple choice exam has 100 questions.Each question has five choices.What would be the approximate probability that a "guesser" could achieve a score of 30 or more?

Light bulbs are normally distributed with an average lifetime of 1000 hours and a standard deviation of 250 hours.The probability that a light bulb picked at random will last less than 1500 hours is about:

A triangular distribution can be skewed either left or right.

The area under the normal curve between the 20^th and 70^th percentiles is equal to:

The normal distribution is a good approximation to the binomial if both π ≥ 10 and n ≥ 10.

Which is the correct Excel formula for the 80^th percentile of a distribution that is N(475,33)?

A random variable X is best described by a continuous uniform distribution from 20 to 45 inclusive.The mean of this distribution is:

Which probability model is most appropriate to describe the waiting time (working days)until an office photocopier breaks down (i.e. ,requires unscheduled maintenance)?

What are the mean and standard deviation for the standard normal distribution?

Overview of Statistics

Data Collection

Describing Data Visually

Descriptive Statistics

Probability

Discrete Probability Distributions

Sampling Distributions and Estimation

One-Sample Hypothesis Tests

Two-Sample Hypothesis Tests

Analysis of Variance

Simple Regression

Multiple Regression

Time-Series Analysis

Chi-Square Tests

Nonparametric Tests

Quality Management

Filters

Exam 7: Continuous Probability Distributions

Any normal distribution has a mean of 0 and a standard deviation of 1.

Could this function be a PDF?

If arrivals follow a Poisson distribution,waiting times follow the exponential distribution.

A multiple choice exam has 100 questions.Each question has five choices.What would be the approximate probability that a "guesser" could achieve a score of 30 or more?

Light bulbs are normally distributed with an average lifetime of 1000 hours and a standard deviation of 250 hours.The probability that a light bulb picked at random will last less than 1500 hours is about:

A triangular distribution can be skewed either left or right.

The area under the normal curve between the 20th and 70th percentiles is equal to:

The normal distribution is a good approximation to the binomial if both π ≥ 10 and n ≥ 10.

Which is the correct Excel formula for the 80th percentile of a distribution that is N(475,33)?

A random variable X is best described by a continuous uniform distribution from 20 to 45 inclusive.The mean of this distribution is:

Which probability model is most appropriate to describe the waiting time (working days)until an office photocopier breaks down (i.e. ,requires unscheduled maintenance)?

What are the mean and standard deviation for the standard normal distribution?

Overview of Statistics

Data Collection

Describing Data Visually

Descriptive Statistics

Probability

Discrete Probability Distributions

Sampling Distributions and Estimation

One-Sample Hypothesis Tests

Two-Sample Hypothesis Tests

Analysis of Variance

Simple Regression

Multiple Regression

Time-Series Analysis

Chi-Square Tests

Nonparametric Tests

Quality Management

Filters

The area under the normal curve between the 20^th and 70^th percentiles is equal to:

Which is the correct Excel formula for the 80^th percentile of a distribution that is N(475,33)?