Question 1

A discrete random variable X may assume an (infinitely) uncountable number of distinct values.

Accepted Answer

A) True 
 B)False  False

Question 2

An investor has a $100,000 portfolio of which $75,000 has been invested in Stock A and the remainder in Stock B. Other characteristics of the portfolio are shown in the accompanying table.   The expected return of the portfolio is ________.

Accepted Answer

A)  6.30% 
B)  6.75% 
C)  7.38% 
D)  13.50% 
A)  6.30% 
B)  6.75% 
C)  7.38% 
D)  13.50% C

Question 3

A probability distribution of a continuous random variable X gives the probability that X takes on a particular value x, P(X = x).

Accepted Answer

A) True 
 B)False  False

Question 4

Sam is a trucker and believes that for every 60 miles he drives on the freeway in Indiana, there is an average of two state troopers checking his speed with a radar gun.
A) What is the probability that at least one trooper is checking his speed on a randomly selected 60-mile stretch?
B) What is the probability that exactly three troopers are checking his speed on a randomly selected 60-mile stretch?
C) Sam drives 240 miles a day. What is the average number of state troopers who check his speed on a given day?
D) Sam drives 240 miles a day. What is the probability that exactly five troopers check Sam's speed on a randomly selected day?

Accepted Answer

a. 0.8647

Question 5

Given the information in the accompanying table, calculate the correlation coefficient between the returns on Stocks A and B.

Accepted Answer

A)  -0.212 
B)  -0.167 
C)  0.167 
D)  0.212 
A)  -0.212 
B)  -0.167 
C)  0.167 
D)  0.212

Question 6

An Excel's function ________ is used for calculating Poisson probabilities.

Accepted Answer

The answer of An Excel's function ________ is used for...

Question 7

According to geologists, the San Francisco Bay Area experiences five earthquakes with a magnitude of 6.5 or greater every 100 years. What is the expected value of the number of earthquakes with a magnitude of 6.5 or greater striking the San Francisco Bay Area in the next 40 years?

Accepted Answer

A)  1.414 
B)  2.000 
C)  2.236 
D)  5.000 
A)  1.414 
B)  2.000 
C)  2.236 
D)  5.000

Question 8

Consider the following cumulative distribution function for the discrete random variable X.   What is the probability that X is greater than 2?

Accepted Answer

A)  0.14 
B)  0.30 
C)  0.44 
D)  0.56 
A)  0.14 
B)  0.30 
C)  0.44 
D)  0.56

Question 9

Forty-four percent of consumers with credit cards carry balances from month to month. Four consumers with credit cards are randomly selected. What is the probability that all consumers carry a credit card balance?

Accepted Answer

A)  0.1015 
B)  0.0375 
C)  0.3133 
D)  0.1390 
A)  0.1015 
B)  0.0375 
C)  0.3133 
D)  0.1390

Question 10

The relationship between the variance and the standard deviation is such that the standard deviation is the positive square root of the variance.

Accepted Answer

A) True 
 B)False

Question 11

The hypergeometric probability distribution is appropriate in applications where we cannot assume the trials are ________.

Accepted Answer

The answer of The hypergeometric probability distribution is appropriate in...

Question 12

Which of the following can be represented by a discrete random variable?

Accepted Answer

A)  The circumference of a randomly generated circle 
B)  The time of a flight between Chicago and New York 
C)  The number of defective light bulbs in a sample of five 
D)  The average distance achieved in a series of long jumps 
A)  The circumference of a randomly generated circle 
B)  The time of a flight between Chicago and New York 
C)  The number of defective light bulbs in a sample of five 
D)  The average distance achieved in a series of long jumps

Question 13

For a particular clothing store, a marketing firm finds that 16% of $10-off coupons delivered by mail are redeemed. Suppose six customers are randomly selected and are mailed $10-off coupons. What is the expected number of coupons that will be redeemed?

Accepted Answer

A)  0.81 
B)  0.96 
C)  3.42 
D)  5.04 
A)  0.81 
B)  0.96 
C)  3.42 
D)  5.04

Question 14

According to the Mortgage Bankers Association, 8% of U.S. mortgages were delinquent last year. A delinquent mortgage is one that has missed at least one payment but has not yet gone to foreclosure. A random sample of eight mortgages was selected. What is the probability that exactly one of these mortgages is delinquent?

Accepted Answer

A)  0.1296 
B)  0.3570 
C)  0.4926 
D)  0.6157 
A)  0.1296 
B)  0.3570 
C)  0.4926 
D)  0.6157

Question 15

Studies have shown that bats can consume an average of 10 mosquitoes per minute. What is the probability that a bat consumes four mosquitoes in a 30-second interval?

Accepted Answer

A)  0.1404 
B)  0.1755 
C)  0.3159 
D)  0.0189 
A)  0.1404 
B)  0.1755 
C)  0.3159 
D)  0.0189

Question 16

A roll of steel is manufactured on a processing line. The anticipated number of defects in a 10-foot segment of this roll is two. What is the probability of no defects in 10 feet of steel?

Accepted Answer

A)  0.0002 
B)  0.1353 
C)  0.1804 
D)  0.8647 
A)  0.0002 
B)  0.1353 
C)  0.1804 
D)  0.8647

Question 17

Studies have shown that bats can consume an average of 10 mosquitoes per minute. What is the probability that a bat does not consume any mosquitoes in a 30-second interval?

Accepted Answer

A)  0.0067 
B)  0.1755 
C)  0.0023 
D)  0.0090 
A)  0.0067 
B)  0.1755 
C)  0.0023 
D)  0.0090

Question 18

On a particular production line, the likelihood that a light bulb is defective is 5%. Ten light bulbs are randomly selected. What is the probability that at most 3 of the light bulbs will be defective?

Accepted Answer

A)  0.0105 
B)  0.0115 
C)  0.9885 
D)  0.9990 
A)  0.0105 
B)  0.0115 
C)  0.9885 
D)  0.9990

Question 19

Lisa is in a free-throw shooting contest where each contestant attempts 10 free throws. On average, Lisa makes 77% of the free throws she attempts.
A) What is the probability that she makes exactly eight free throws?
B) What is the probability she makes at least nine free throws?
C) What is the probability she makes fewer than nine free throws?
D) Lisa is competing against Bill to see who can make the most free throws in 10 attempts. Suppose Bill goes first and makes seven. Should we expect Lisa to make at least as many as Bill? Explain.

Accepted Answer

a. 0.2942
b. 0.2921
c. 0.7079

Question 20

A telemarketer knows that, on average, he is able to make three sales in a 30-minute period. Suppose the number of sales he can make in a given time period is Poisson distributed.
A) What is the probability that he makes exactly four sales in a 30-minute period?
B) What is the probability that he makes at least two sales in a 30-minute period?
C) What is the probability that he makes five sales in an hour-long period?

Accepted Answer

a. 0.1680
b. 0.8010
c. 0.1606

A discrete random variable X may assume an (infinitely) uncountable number of distinct values.

An investor has a $100,000 portfolio of which $75,000 has been invested in Stock A and the remainder in Stock B. Other characteristics of the portfolio are shown in the accompanying table. The expected return of the portfolio is ________.

A probability distribution of a continuous random variable X gives the probability that X takes on a particular value x, P(X = x).

Given the information in the accompanying table, calculate the correlation coefficient between the returns on Stocks A and B.

An Excel's function ________ is used for calculating Poisson probabilities.

According to geologists, the San Francisco Bay Area experiences five earthquakes with a magnitude of 6.5 or greater every 100 years. What is the expected value of the number of earthquakes with a magnitude of 6.5 or greater striking the San Francisco Bay Area in the next 40 years?

Consider the following cumulative distribution function for the discrete random variable X. What is the probability that X is greater than 2?

Forty-four percent of consumers with credit cards carry balances from month to month. Four consumers with credit cards are randomly selected. What is the probability that all consumers carry a credit card balance?

The relationship between the variance and the standard deviation is such that the standard deviation is the positive square root of the variance.

The hypergeometric probability distribution is appropriate in applications where we cannot assume the trials are ________.

Which of the following can be represented by a discrete random variable?

For a particular clothing store, a marketing firm finds that 16% of $10-off coupons delivered by mail are redeemed. Suppose six customers are randomly selected and are mailed $10-off coupons. What is the expected number of coupons that will be redeemed?

Studies have shown that bats can consume an average of 10 mosquitoes per minute. What is the probability that a bat consumes four mosquitoes in a 30-second interval?

A roll of steel is manufactured on a processing line. The anticipated number of defects in a 10-foot segment of this roll is two. What is the probability of no defects in 10 feet of steel?

Studies have shown that bats can consume an average of 10 mosquitoes per minute. What is the probability that a bat does not consume any mosquitoes in a 30-second interval?

On a particular production line, the likelihood that a light bulb is defective is 5%. Ten light bulbs are randomly selected. What is the probability that at most 3 of the light bulbs will be defective?

Statistics and Data

Tabular and Graphical Methods

Numerical Descriptive Measures

Introduction to Probability

Continuous 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 5: Discrete Probability Distributions

A discrete random variable X may assume an (infinitely) uncountable number of distinct values.

An investor has a $100,000 portfolio of which $75,000 has been invested in Stock A and the remainder in Stock B. Other characteristics of the portfolio are shown in the accompanying table. The expected return of the portfolio is ________.

A probability distribution of a continuous random variable X gives the probability that X takes on a particular value x, P(X = x).

Given the information in the accompanying table, calculate the correlation coefficient between the returns on Stocks A and B.

An Excel's function ________ is used for calculating Poisson probabilities.

According to geologists, the San Francisco Bay Area experiences five earthquakes with a magnitude of 6.5 or greater every 100 years. What is the expected value of the number of earthquakes with a magnitude of 6.5 or greater striking the San Francisco Bay Area in the next 40 years?

Consider the following cumulative distribution function for the discrete random variable X. What is the probability that X is greater than 2?

Forty-four percent of consumers with credit cards carry balances from month to month. Four consumers with credit cards are randomly selected. What is the probability that all consumers carry a credit card balance?

The relationship between the variance and the standard deviation is such that the standard deviation is the positive square root of the variance.

The hypergeometric probability distribution is appropriate in applications where we cannot assume the trials are ________.

Which of the following can be represented by a discrete random variable?

For a particular clothing store, a marketing firm finds that 16% of $10-off coupons delivered by mail are redeemed. Suppose six customers are randomly selected and are mailed $10-off coupons. What is the expected number of coupons that will be redeemed?

Studies have shown that bats can consume an average of 10 mosquitoes per minute. What is the probability that a bat consumes four mosquitoes in a 30-second interval?

A roll of steel is manufactured on a processing line. The anticipated number of defects in a 10-foot segment of this roll is two. What is the probability of no defects in 10 feet of steel?

Studies have shown that bats can consume an average of 10 mosquitoes per minute. What is the probability that a bat does not consume any mosquitoes in a 30-second interval?

On a particular production line, the likelihood that a light bulb is defective is 5%. Ten light bulbs are randomly selected. What is the probability that at most 3 of the light bulbs will be defective?

Statistics and Data

Tabular and Graphical Methods

Numerical Descriptive Measures

Introduction to Probability

Continuous 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