Question 1

The Excel provides function _________ to compute probabilities for the exponential distribution.

Accepted Answer

The answer of The Excel provides function _________ to compute...

Question 2

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 less than 20 minutes?

Accepted Answer

A)  30.15% 
B)  34.09% 
C)  65.91% 
D)  69.85% 
A)  30.15% 
B)  34.09% 
C)  65.91% 
D)  69.85%

Question 3

When attending a movie,patrons are interested in avoiding the pre-movie trivia games,ads,and previews.It is known that the previews begin at the scheduled movie start time and they last between 5 and 15 minutes.Assume that the time of the previews is uniformly distributed.
a.Find the expected time and variance of the movie preview duration.
b.What is the probability that on a given day the previews last between 10 and 12 minutes?

Accepted Answer

a.10 and 8

Question 4

Sarah's portfolio has an expected annual return at 8%,with an annual standard deviation at 12%.If her investment returns are normally distributed,then in any given year Sarah has approximately ______________________.

Accepted Answer

A)  A 50% chance that the actual return will be greater than 8% 
B)  About a 68% chance that the actual return will fall within 4% and 20% 
C)  About a 68% chance that the actual return will fall within -20% and 20% 
D)  About a 95% chance that the actual return will fall within -4% and 28%. 
A)  A 50% chance that the actual return will be greater than 8% 
B)  About a 68% chance that the actual return will fall within 4% and 20% 
C)  About a 68% chance that the actual return will fall within -20% and 20% 
D)  About a 95% chance that the actual return will fall within -4% and 28%.

Question 5

The probability density function of a continuous random variable is the counterpart to the probability mass function of a discrete random variable.

Accepted Answer

A) True 
 B)False

Question 6

We can use the _______ transformation,x = µ + zσ,to compute x values for given probabilities.

Accepted Answer

The answer of We can use the _______ transformation,x =...

Question 7

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 at least six years without requiring repairs?

Accepted Answer

A)  0.7769 
B)  0.3456 
C)  0.6544 
D)  0.2231 
A)  0.7769 
B)  0.3456 
C)  0.6544 
D)  0.2231

Question 8

Cumulative distribution functions can only be used to compute probabilities for continuous random variables.

Accepted Answer

A) True 
 B)False

Question 9

The probability that a normal random variable is less than its mean is ___.

Accepted Answer

A)  0.0 
B)  0.5 
C)  1.0 
D)  Cannot be determined 
A)  0.0 
B)  0.5 
C)  1.0 
D)  Cannot be determined

Question 10

An analyst is forecasting net income for Excellence Corporation for the next fiscal year.Her low-end estimate of net income is $250,000,and her high-end estimate is $350,000.Prior research allows her to assume that net income follows a continuous uniform distribution.The probability that net income will be greater than or equal to $337,500 is _______.

Accepted Answer

A)  12.5% 
B)  29.6% 
C)  87.5% 
D)  96.4% 
A)  12.5% 
B)  29.6% 
C)  87.5% 
D)  96.4%

Question 11

Customers arrive at a drive-through teller window of a bank.They stay in line when the teller is busy.The service time is exponentially distributed with a mean of four minutes.
a.What is the probability that the next customer in line will take longer than seven minutes to be served?
b.What is the probability that the next customer in line will take less than eight minutes to be served?
c.What is the probability that the next customer in line will take between three and six minutes to be served?

Accepted Answer

a.0.1738;

Question 12

The starting salary of an administrative assistant is normally distributed with a mean of $50,000 and a standard deviation of $2,500.We know that the probability of a randomly selected administrative assistant making a salary between μ - x and μ + x is 0.7416.Find the salary range referred to in this statement.

Accepted Answer

A)  $42,825 to $52,825 
B)  $42,825 to $57,175 
C)  $47,175 to $52,825 
D)  $47,175 to $57,175 
A)  $42,825 to $52,825 
B)  $42,825 to $57,175 
C)  $47,175 to $52,825 
D)  $47,175 to $57,175

Question 13

A normal random variable X has a mean of 17 and a variance of 5.
a.Find the value x for which P(X ≤ x)= 0.0020.
b.Find the value of x for which P(X > x)= 0.0122.

Accepted Answer

The answer of A normal random variable X has a...

Question 14

Let the lifetime of a new Jet Ski be represented by a lognormal variable,   where X is normally distributed.Let the mean of the lifetime of the Jet Ski be six years with a standard deviation of three years. What proportion of the Jet Skis will last less than seven years?

Accepted Answer

A)  0.2877 
B)  0.3707 
C)  0.6293 
D)  0.7123 
A)  0.2877 
B)  0.3707 
C)  0.6293 
D)  0.7123

Question 15

Let X be normally distributed with mean µ = 250 and standard deviation σ = 80.Find the value x such that P(X ≤ x)= 0.9394.

Accepted Answer

A)  -1.55 
B)  1.55 
C)  126 
D)  374 
A)  -1.55 
B)  1.55 
C)  126 
D)  374

Question 16

An investment consultant tells her client that the probability of making a positive return with her suggested portfolio is 0.90.What is the risk,measured by standard deviation that this investment manager has assumed in his calculation if it is known that returns from her suggested portfolio are normally distributed with a mean of 6%?

Accepted Answer

A)  1.28% 
B)  4.69% 
C)  6.00% 
D)  10.0% 
A)  1.28% 
B)  4.69% 
C)  6.00% 
D)  10.0%

Question 17

The East Los Angeles Interchange is the busiest freeway interchange in the world.In 2008,an average of 550,000 cars passed through the intersection per day with a standard deviation of 100,000.What is the probability more than 620,000 use the interchange on a random day? Assume the number of cars on the interchange is approximately normally distributed.

Accepted Answer

The answer of The East Los Angeles Interchange is the...

Question 18

You are considering the risk-return profile of two mutual funds for investment.The relatively risky fund promises an expected return of 9%,with a standard deviation of 12%.The relatively less risky fund promises an expected return and standard deviation of 5% and 8%,respectively.
a.Which mutual fund will you pick if your objective is to minimize the probability of earning a negative return?
b.Which mutual fund will you pick if your objective is to maximize the probability of earning a return between 8% and 12%?

Accepted Answer

a.risky fu

Question 19

The weight of competition pumpkins at the Circleville Pumpkin Show in Circleville,Ohio,can be represented by a normal distribution with a mean of 703 pounds and a standard deviation of 347 pounds.
a.Find the probability that a randomly selected pumpkin weighs at least 1622 pounds.
b.Find the probability that a randomly selected pumpkin weighs between 465.1 and 1622 pounds.

Accepted Answer

The answer of The weight of competition pumpkins at the...

Question 20

The mean and standard deviation of the continuous uniform distribution are equal.

Accepted Answer

A) True 
 B)False

The Excel provides function _________ to compute probabilities for the exponential distribution.

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 less than 20 minutes?

Sarah's portfolio has an expected annual return at 8%,with an annual standard deviation at 12%.If her investment returns are normally distributed,then in any given year Sarah has approximately ______________________.

The probability density function of a continuous random variable is the counterpart to the probability mass function of a discrete random variable.

We can use the _______ transformation,x = µ + zσ,to compute x values for given probabilities.

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 at least six years without requiring repairs?

Cumulative distribution functions can only be used to compute probabilities for continuous random variables.

The probability that a normal random variable is less than its mean is ___.

A normal random variable X has a mean of 17 and a variance of 5. a.Find the value x for which P(X ≤ x)= 0.0020. b.Find the value of x for which P(X > x)= 0.0122.

Let the lifetime of a new Jet Ski be represented by a lognormal variable, where X is normally distributed.Let the mean of the lifetime of the Jet Ski be six years with a standard deviation of three years. What proportion of the Jet Skis will last less than seven years?

Let X be normally distributed with mean µ = 250 and standard deviation σ = 80.Find the value x such that P(X ≤ x)= 0.9394.

The mean and standard deviation of the continuous uniform distribution are equal.

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 Excel provides function _________ to compute probabilities for the exponential distribution.

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 less than 20 minutes?

Sarah's portfolio has an expected annual return at 8%,with an annual standard deviation at 12%.If her investment returns are normally distributed,then in any given year Sarah has approximately ______________________.

The probability density function of a continuous random variable is the counterpart to the probability mass function of a discrete random variable.

We can use the _______ transformation,x = µ + zσ,to compute x values for given probabilities.

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 at least six years without requiring repairs?

Cumulative distribution functions can only be used to compute probabilities for continuous random variables.

The probability that a normal random variable is less than its mean is ___.

A normal random variable X has a mean of 17 and a variance of 5. a.Find the value x for which P(X ≤ x)= 0.0020. b.Find the value of x for which P(X > x)= 0.0122.

Let the lifetime of a new Jet Ski be represented by a lognormal variable, where X is normally distributed.Let the mean of the lifetime of the Jet Ski be six years with a standard deviation of three years. What proportion of the Jet Skis will last less than seven years?

Let X be normally distributed with mean µ = 250 and standard deviation σ = 80.Find the value x such that P(X ≤ x)= 0.9394.

The mean and standard deviation of the continuous uniform distribution are equal.

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