Question 1

The probability density function for a continuous uniform distribution is positive for all values between -∞ and +∞.

Accepted Answer

A) True 
 B)False

Question 2

The lognormal distribution is clearly negatively skewed for σ > 1.

Accepted Answer

A) True 
 B)False

Question 3

The salary of teachers in a particular school district is normally distributed with a mean of $50,000 and a standard deviation of $2,500.Due to budget limitations,it has been decided that the teachers who are in the top 2.5% of the salaries would not get a raise.What is the salary level that divides the teachers into one group that gets a raise and one that doesn't?

Accepted Answer

A)  -1.96 
B)  1.96 
C)  45,100 
D)  54,900 
A)  -1.96 
B)  1.96 
C)  45,100 
D)  54,900

Question 4

Which of the following is correct?

Accepted Answer

A)  A continuous random variable has a probability density function but not a cumulative distribution function. 
B)  A discrete random variable has a probability mass function but not a cumulative distribution function. 
C)  A continuous random variable has a probability mass function,and a discrete random variable has a probability density function. 
D)  A continuous random variable has a probability density function,and a discrete random variable has a probability mass function. 
A)  A continuous random variable has a probability density function but not a cumulative distribution function. 
B)  A discrete random variable has a probability mass function but not a cumulative distribution function. 
C)  A continuous random variable has a probability mass function,and a discrete random variable has a probability density function. 
D)  A continuous random variable has a probability density function,and a discrete random variable has a probability mass function.

Question 5

A producer has a history of making bad movies.The movies he has produced have averaged $160,000 dollars at the box office with a standard deviation of $185,000.He thinks his latest movie will be a huge hit.How much will the movie earn at the box office if it is only expected to earn that much or more 0.5% of the time? (Assume that the profit at the box office is normally distributed. )

Accepted Answer

$636,375
LO: 06-05
T

Question 6

The mean travel time to work is 25.2 minutes (U.S.Census 2010).Further,suppose that commute time follows a log-normal distribution with a standard deviation of 10 minutes. What is the probability a randomly selected U.S.worker has a commute time of more than half an hour?

Accepted Answer

A)  25.78% 
B)  31.56% 
C)  68.44% 
D)  74.22% 
A)  25.78% 
B)  31.56% 
C)  68.44% 
D)  74.22%

Question 7

What can be said about the expected value and standard deviation of an exponential distribution?

Accepted Answer

A)  The expected value is equal to the standard deviation. 
B)  The expected value is equal to the square of the standard deviation. 
C)  The expected value is equal to the reciprocal of the standard deviation. 
D)  The expected value is equal to the square root of the standard deviation. 
A)  The expected value is equal to the standard deviation. 
B)  The expected value is equal to the square of the standard deviation. 
C)  The expected value is equal to the reciprocal of the standard deviation. 
D)  The expected value is equal to the square root of the standard deviation.

Question 8

The exponential distribution is related to the Poisson distribution.

Accepted Answer

A) True 
 B)False

Question 9

You are planning a May camping trip to Denali National Park in Alaska and want to make sure your sleeping bag is warm enough.The average low temperature in the park for May follows a normal distribution with a mean of 32°F and a standard deviation of 8°F. Above what temperature must the sleeping bag be suited such that the temperature will be too cold only 5% of the time?

Accepted Answer

A)  -1.645 
B)  1.645 
C)  18.84 
D)  45.16 
A)  -1.645 
B)  1.645 
C)  18.84 
D)  45.16

Question 10

Find the mean of the lognormal variable if the mean and standard deviation of the underlying normal variable are 2 and 0.8,respectively.

Accepted Answer

A)  0.69 
B)  2.32 
C)  10.18 
D)  11.02 
A)  0.69 
B)  2.32 
C)  10.18 
D)  11.02

Question 11

Which of the following does not represent a continuous random variable?

Accepted Answer

A)  Height of oak trees in a park. 
B)  Heights and weights of newborn babies. 
C)  Time of a flight between Chicago and New York. 
D)  The number of customer arrivals to a bank between 10 am and 11 am. 
A)  Height of oak trees in a park. 
B)  Heights and weights of newborn babies. 
C)  Time of a flight between Chicago and New York. 
D)  The number of customer arrivals to a bank between 10 am and 11 am.

Question 12

Find the variance of the lognormal variable if the mean and variance of the underlying normal variable are 2 and 1,respectively.

Accepted Answer

A)  0 
B)  12.18 
C)  15.97 
D)  255.02 
A)  0 
B)  12.18 
C)  15.97 
D)  255.02

Question 13

Let house prices in a rich community in Chicago be represented by ,where X is normally distributed.Suppose the mean house price is $1.8 million and the standard deviation is $0.4 million.What is the proportion of the houses that are worth more than $2.5 million?

Accepted Answer

The answer of Let house prices in a rich community...

Question 14

On average,a certain kind of kitchen appliance requires repairs once every four years.Assume that the times between repairs are exponentially distributed.Which of the following Excel commands computes the probability that the appliance will work no more than three years without requiring repairs?

Accepted Answer

A)  0.3254 
B)  0.6744 
C)  0.5276 
D)  0.4724 
A)  0.3254 
B)  0.6744 
C)  0.5276 
D)  0.4724

Question 15

If an exponential distribution has the rate parameter λ = 5,what is its variance?

Accepted Answer

A)  5 
B)  1/5 
C)  1/25 
D)  5/2 
A)  5 
B)  1/5 
C)  1/25 
D)  5/2

Question 16

You are planning a May camping trip to Denali National Park in Alaska and want to make sure your sleeping bag is warm enough.The average low temperature in the park for May follows a normal distribution with a mean of 32°F and a standard deviation of 8°F. An inexpensive bag you are considering advertises to be good for temperatures down to 38°F.What is the probability that the bag will not be warm enough?

Accepted Answer

A)  0.2266 
B)  0.2734 
C)  0.7500 
D)  0.7734 
A)  0.2266 
B)  0.2734 
C)  0.7500 
D)  0.7734

Question 17

The average wait time to see a doctor at a maternity ward is 16 minutes.What is the probability that a patient will have to wait between 20 and 30 minutes before seeing a doctor? Suppose the wait time is exponentially distributed.

Accepted Answer

The answer of The average wait time to see a...

Question 18

Patients scheduled to see their primary care physician at a particular hospital wait,on average,an additional eight minutes after their appointment is scheduled to start.Assume the time that patients wait is exponentially distributed. What is the probability a randomly selected patient will see the doctor within five minutes of the scheduled time?

Accepted Answer

A)  0.2019 
B)  0.4647 
C)  0.5353 
D)  0.7981 
A)  0.2019 
B)  0.4647 
C)  0.5353 
D)  0.7981

Question 19

Examples of random variables that closely follow a normal distribution include the age and the class year designation of a college student.

Accepted Answer

A) True 
 B)False

Question 20

According the empirical rule for normally distributed variables,75% of the values fall within one standard deviation of the mean.

Accepted Answer

A) True 
 B)False

The probability density function for a continuous uniform distribution is positive for all values between -∞ and +∞.

The lognormal distribution is clearly negatively skewed for σ > 1.

Which of the following is correct?

The mean travel time to work is 25.2 minutes (U.S.Census 2010).Further,suppose that commute time follows a log-normal distribution with a standard deviation of 10 minutes. What is the probability a randomly selected U.S.worker has a commute time of more than half an hour?

What can be said about the expected value and standard deviation of an exponential distribution?

The exponential distribution is related to the Poisson distribution.

Find the mean of the lognormal variable if the mean and standard deviation of the underlying normal variable are 2 and 0.8,respectively.

Which of the following does not represent a continuous random variable?

Find the variance of the lognormal variable if the mean and variance of the underlying normal variable are 2 and 1,respectively.

Let house prices in a rich community in Chicago be represented by ,where X is normally distributed.Suppose the mean house price is $1.8 million and the standard deviation is $0.4 million.What is the proportion of the houses that are worth more than $2.5 million?

On average,a certain kind of kitchen appliance requires repairs once every four years.Assume that the times between repairs are exponentially distributed.Which of the following Excel commands computes the probability that the appliance will work no more than three years without requiring repairs?

If an exponential distribution has the rate parameter λ = 5,what is its variance?

The average wait time to see a doctor at a maternity ward is 16 minutes.What is the probability that a patient will have to wait between 20 and 30 minutes before seeing a doctor? Suppose the wait time is exponentially distributed.

Examples of random variables that closely follow a normal distribution include the age and the class year designation of a college student.

According the empirical rule for normally distributed variables,75% of the values fall within one standard deviation of the mean.

Statistics and Data

Tabular and Graphical Methods

Numerical Descriptive Measures

Basic Probability Concepts

Discrete Probability Distributions

Sampling and Sampling Distributions

Interval Estimation

Hypothesis Testing

Statistical Inference Concerning Two Populations

Statistical Inference Concerning Variance

Chi-Square Tests

Analysis of Variance

Regression Analysis

Inference With Regression Models

Regression Models for Nonlinear Relationships

Regression Models With Dummy Variables

Time Series and Forecasting

Returns, Index Numbers and Inflation

Nonparametric Tests

Filters

Exam 6: Continuous Probability Distributions

The probability density function for a continuous uniform distribution is positive for all values between -∞ and +∞.

The lognormal distribution is clearly negatively skewed for σ > 1.

Which of the following is correct?

The mean travel time to work is 25.2 minutes (U.S.Census 2010).Further,suppose that commute time follows a log-normal distribution with a standard deviation of 10 minutes. What is the probability a randomly selected U.S.worker has a commute time of more than half an hour?

What can be said about the expected value and standard deviation of an exponential distribution?

The exponential distribution is related to the Poisson distribution.

Find the mean of the lognormal variable if the mean and standard deviation of the underlying normal variable are 2 and 0.8,respectively.

Which of the following does not represent a continuous random variable?

Find the variance of the lognormal variable if the mean and variance of the underlying normal variable are 2 and 1,respectively.

Let house prices in a rich community in Chicago be represented by ,where X is normally distributed.Suppose the mean house price is $1.8 million and the standard deviation is $0.4 million.What is the proportion of the houses that are worth more than $2.5 million?

On average,a certain kind of kitchen appliance requires repairs once every four years.Assume that the times between repairs are exponentially distributed.Which of the following Excel commands computes the probability that the appliance will work no more than three years without requiring repairs?

If an exponential distribution has the rate parameter λ = 5,what is its variance?

The average wait time to see a doctor at a maternity ward is 16 minutes.What is the probability that a patient will have to wait between 20 and 30 minutes before seeing a doctor? Suppose the wait time is exponentially distributed.

Examples of random variables that closely follow a normal distribution include the age and the class year designation of a college student.

According the empirical rule for normally distributed variables,75% of the values fall within one standard deviation of the mean.

Statistics and Data

Tabular and Graphical Methods

Numerical Descriptive Measures

Basic Probability Concepts

Discrete Probability Distributions

Sampling and Sampling Distributions

Interval Estimation

Hypothesis Testing

Statistical Inference Concerning Two Populations

Statistical Inference Concerning Variance

Chi-Square Tests

Analysis of Variance

Regression Analysis

Inference With Regression Models

Regression Models for Nonlinear Relationships

Regression Models With Dummy Variables

Time Series and Forecasting

Returns, Index Numbers and Inflation

Nonparametric Tests

Filters