Question 1

Of the following,the one that most resembles a Poisson random variable is the number of

Accepted Answer

A) heads in 200 flips of a fair coin. 
B) annual power failures at your residence. 
C) face cards in a bridge hand of 13 cards. 
D) defective CDs in a spool containing 15 CDs. 
A) heads in 200 flips of a fair coin. 
B) annual power failures at your residence. 
C) face cards in a bridge hand of 13 cards. 
D) defective CDs in a spool containing 15 CDs. B

Question 2

A discrete random variable has a countable number of distinct values.

Accepted Answer

A) True 
 B)False  True

Question 3

During a randomly-chosen 24-hour period,which model best describes the number of mothers who deliver twins in a small hospital?

Accepted Answer

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

Question 4

Which model best describes the number of nonworking web URLs ("This page cannot be displayed")you encounter in a randomly chosen minute while surfing websites for Florida vacation rental condos?

Accepted Answer

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

Question 5

A fair die is rolled.If it comes up 1 or 2 you win $2.If it comes up 3,4,5,or 6,you lose $1.Calculate the expected winnings.

Accepted Answer

A) $0.00 
B) $1.00 
C) $0.50 
D) $0.25 
A) $0.00 
B) $1.00 
C) $0.50 
D) $0.25

Question 6

The Poisson distribution describes the number of occurrences within a randomly chosen unit of time or space.

Accepted Answer

A) True 
 B)False

Question 7

Hardluck Harry has a batting average of 0.200 (i.e. ,a 20 percent chance of a hit each time he's at bat).Scouts for a rival baseball club secretly observe Harry's performance in 12 random times at bat.What is the probability that Harry will get more than 2 hits?

Accepted Answer

A) 0.2055 
B) 0.2362 
C) 0.7946 
D) 0.4417 
A) 0.2055 
B) 0.2362 
C) 0.7946 
D) 0.4417

Question 8

If 5 percent of automobiles in Oakland County have one burned-out headlight,what is the probability that,in a sample of 10 automobiles,none will have a burned-out headlight?

Accepted Answer

A) 0.5987 
B) 0.3151 
C) 0.0116 
D) 0.1872 
A) 0.5987 
B) 0.3151 
C) 0.0116 
D) 0.1872

Question 9

The probability that an Oxnard University student is carrying a backpack is 0.70.If 10 students are observed at random,what is the probability that fewer than 7 will be carrying backpacks?

Accepted Answer

A) 0.3504 
B) 0.2001 
C) 0.6177 
D) 0.2668 
A) 0.3504 
B) 0.2001 
C) 0.6177 
D) 0.2668

Question 10

The Poisson distribution has only one parameter.

Accepted Answer

A) True 
 B)False

Question 11

The expected value of a random variable X is 115 and the standard deviation is 21.The standard deviation of the random variable Y = 3X − 10 is

Accepted Answer

A) 63 
B) 6.48 
C) 53 
D) 41 
A) 63 
B) 6.48 
C) 53 
D) 41

Question 12

Ephemeral Services Corporation (ESCO)knows that nine other companies besides ESCO are bidding for a $900,000 government contract.Each company has an equal chance of being awarded the contract.If ESCO has already spent $100,000 in developing its bidding proposal,what is its expected net profit?

Accepted Answer

A) $100,000 
B) $90,000 
C) −$10,000 
D) $0 
A) $100,000 
B) $90,000 
C) −$10,000 
D) $0

Question 13

A network has three independent file servers,each with 90 percent reliability.The probability that the network will be functioning correctly (at least one server is working)at a given time is

Accepted Answer

A) 99.9 percent. 
B) 97.2 percent. 
C) 95.9 percent. 
D) 72.9 percent. 
A) 99.9 percent. 
B) 97.2 percent. 
C) 95.9 percent. 
D) 72.9 percent.

Question 14

If X is a discrete uniform random variable ranging from one to eight,what is its mean?

Accepted Answer

A) 4.0 
B) 4.5 
C) 5.0 
D) 5.5 
A) 4.0 
B) 4.5 
C) 5.0 
D) 5.5

Question 15

Which distribution is most nearly appropriate to describe the number of fatalities in Texas in a given year due to poisonous snakebites?

Accepted Answer

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

Question 16

Cars are arriving at a toll booth at a rate of four per minute.What is the probability that exactly eight cars will arrive in the next two minutes?

Accepted Answer

A) 0.0349 
B) 0.1396 
C) 0.9666 
D) 0.0005 
A) 0.0349 
B) 0.1396 
C) 0.9666 
D) 0.0005

Question 17

A stock portfolio consists of two stocks X and Y.Their daily closing prices are independent random variables with standard deviations σX = 2.51 and σY = 5.22.What is the standard deviation of the sum of the closing prices of these two stocks?

Accepted Answer

A) 33.55 
B) 6.48 
C) 7.73 
D) 5.79 
A) 33.55 
B) 6.48 
C) 7.73 
D) 5.79

Question 18

The expected value of a random variable is its mean.

Accepted Answer

A) True 
 B)False

Question 19

The probability that a visitor to an animal shelter will adopt a dog is 0.20.Out of nine visits,what is the probability that at least one dog will be adopted?

Accepted Answer

A) 0.8658 
B) 0.3020 
C) 0.5639 
D) 0.1342 
A) 0.8658 
B) 0.3020 
C) 0.5639 
D) 0.1342

Question 20

The variance will reach a maximum in a binomial distribution when

Accepted Answer

A) π = 1 and 1−π = 0. 
B) π = ¼ and 1−π = ¾. 
C) π = ½ and 1−π = ½. 
D) π = 0 and 1−π = 1. 
A) π = 1 and 1−π = 0. 
B) π = ¼ and 1−π = ¾. 
C) π = ½ and 1−π = ½. 
D) π = 0 and 1−π = 1.

Of the following,the one that most resembles a Poisson random variable is the number of

A discrete random variable has a countable number of distinct values.

During a randomly-chosen 24-hour period,which model best describes the number of mothers who deliver twins in a small hospital?

Which model best describes the number of nonworking web URLs ("This page cannot be displayed")you encounter in a randomly chosen minute while surfing websites for Florida vacation rental condos?

A fair die is rolled.If it comes up 1 or 2 you win $2.If it comes up 3,4,5,or 6,you lose $1.Calculate the expected winnings.

The Poisson distribution describes the number of occurrences within a randomly chosen unit of time or space.

Hardluck Harry has a batting average of 0.200 (i.e. ,a 20 percent chance of a hit each time he's at bat).Scouts for a rival baseball club secretly observe Harry's performance in 12 random times at bat.What is the probability that Harry will get more than 2 hits?

If 5 percent of automobiles in Oakland County have one burned-out headlight,what is the probability that,in a sample of 10 automobiles,none will have a burned-out headlight?

The probability that an Oxnard University student is carrying a backpack is 0.70.If 10 students are observed at random,what is the probability that fewer than 7 will be carrying backpacks?

The Poisson distribution has only one parameter.

The expected value of a random variable X is 115 and the standard deviation is 21.The standard deviation of the random variable Y = 3X − 10 is

Ephemeral Services Corporation (ESCO)knows that nine other companies besides ESCO are bidding for a $900,000 government contract.Each company has an equal chance of being awarded the contract.If ESCO has already spent $100,000 in developing its bidding proposal,what is its expected net profit?

A network has three independent file servers,each with 90 percent reliability.The probability that the network will be functioning correctly (at least one server is working)at a given time is

If X is a discrete uniform random variable ranging from one to eight,what is its mean?

Which distribution is most nearly appropriate to describe the number of fatalities in Texas in a given year due to poisonous snakebites?

Cars are arriving at a toll booth at a rate of four per minute.What is the probability that exactly eight cars will arrive in the next two minutes?

A stock portfolio consists of two stocks X and Y.Their daily closing prices are independent random variables with standard deviations σX = 2.51 and σY = 5.22.What is the standard deviation of the sum of the closing prices of these two stocks?

The expected value of a random variable is its mean.

The probability that a visitor to an animal shelter will adopt a dog is 0.20.Out of nine visits,what is the probability that at least one dog will be adopted?

The variance will reach a maximum in a binomial distribution when

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

Of the following,the one that most resembles a Poisson random variable is the number of

A discrete random variable has a countable number of distinct values.

During a randomly-chosen 24-hour period,which model best describes the number of mothers who deliver twins in a small hospital?

Which model best describes the number of nonworking web URLs ("This page cannot be displayed")you encounter in a randomly chosen minute while surfing websites for Florida vacation rental condos?

A fair die is rolled.If it comes up 1 or 2 you win $2.If it comes up 3,4,5,or 6,you lose $1.Calculate the expected winnings.

The Poisson distribution describes the number of occurrences within a randomly chosen unit of time or space.

Hardluck Harry has a batting average of 0.200 (i.e. ,a 20 percent chance of a hit each time he's at bat).Scouts for a rival baseball club secretly observe Harry's performance in 12 random times at bat.What is the probability that Harry will get more than 2 hits?

If 5 percent of automobiles in Oakland County have one burned-out headlight,what is the probability that,in a sample of 10 automobiles,none will have a burned-out headlight?

The probability that an Oxnard University student is carrying a backpack is 0.70.If 10 students are observed at random,what is the probability that fewer than 7 will be carrying backpacks?

The Poisson distribution has only one parameter.

The expected value of a random variable X is 115 and the standard deviation is 21.The standard deviation of the random variable Y = 3X − 10 is

Ephemeral Services Corporation (ESCO)knows that nine other companies besides ESCO are bidding for a $900,000 government contract.Each company has an equal chance of being awarded the contract.If ESCO has already spent $100,000 in developing its bidding proposal,what is its expected net profit?

A network has three independent file servers,each with 90 percent reliability.The probability that the network will be functioning correctly (at least one server is working)at a given time is

If X is a discrete uniform random variable ranging from one to eight,what is its mean?

Which distribution is most nearly appropriate to describe the number of fatalities in Texas in a given year due to poisonous snakebites?

Cars are arriving at a toll booth at a rate of four per minute.What is the probability that exactly eight cars will arrive in the next two minutes?

A stock portfolio consists of two stocks X and Y.Their daily closing prices are independent random variables with standard deviations σX = 2.51 and σY = 5.22.What is the standard deviation of the sum of the closing prices of these two stocks?

The expected value of a random variable is its mean.

The probability that a visitor to an animal shelter will adopt a dog is 0.20.Out of nine visits,what is the probability that at least one dog will be adopted?

The variance will reach a maximum in a binomial distribution when

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