A stock portfolio consists of two stocks X and Y. Their daily closing prices are correlated random variables with variances σX2 = 3.51 and σY2 = 5.22, and covariance σXY = -1.55. What is the standard deviation of the sum of the closing prices of these two stocks?

A) 5.63 B) 7.18 C) 8.73 D) 2.68 A) 5.63 B) 7.18 C) 8.73 D) 2.68

Exam 6: Discrete Probability Distributions

On Saturday morning, calls arrive at TicketMaster at a rate of 108 calls per hour. What is the probability of fewer than three calls in a randomly chosen minute?

(Multiple Choice)

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Question 21

Which probability model is most nearly appropriate to describe the number of burned-out fluorescent tubes in a classroom with 12 fluorescent tubes, assuming a constant probability of a burned-out tube?

(Multiple Choice)

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Question 22

The expected value of a discrete random variable E(X) is the sum of all X values weighted by their respective probabilities.

(True/False)

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Question 23

Calculating the probability of getting three aces in a hand of five cards dealt from a deck of 52 cards would require the use of a hypergeometric distribution.

(True/False)

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Question 24

The binomial distribution is symmetrical when:

(Multiple Choice)

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Question 25

A stock portfolio consists of two stocks X and Y. Their daily closing prices are correlated random variables with variances σ_X² = 3.51 and σ_Y² = 5.22, and covariance σ_XY = -1.55. What is the standard deviation of the sum of the closing prices of these two stocks?

(Multiple Choice)

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Question 26

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:

(Multiple Choice)

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Question 27

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

(Multiple Choice)

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Question 28

A project has 3 independent stages that must be completed in sequence. The time to complete each stage is a random variable. The standard deviations of the completion times for the stages are σ₁ = 5, σ₂ = 4, σ₃ = 6. The standard deviation of the overall project completion time is:

(Multiple Choice)

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Question 29

The probability that a visitor to an animal shelter will adopt a dog is .20. Out of nine visits, what is the probability that at least one dog will be adopted?

(Multiple Choice)

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Question 30

For which binomial distribution would a Poisson approximation be unacceptable?

(Multiple Choice)

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Question 31

At Ersatz University, the graduating class of 480 includes 96 guest students from Latvia. A sample of 10 students is selected at random to attend a dinner with the Board of Governors. Use the binomial model to obtain the approximate hypergeometric probability that the sample contains at least three Latvian students.

(Multiple Choice)

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Question 32

The probability that a rental car will be stolen is 0.0004. If 3500 cars are rented, what is the approximate Poisson probability that 2 or fewer will be stolen?

(Multiple Choice)

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Question 33

The discrete random variable X is the number of passengers waiting at a bus stop. The table below shows the probability distribution for X. What is the expected value E(X) for this distribution? X 0 1 2 3 Total P(X) 20 40 30 10 1.00

(Multiple Choice)

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Question 34

Based on experience, 60 percent of the women who request a pregnancy test at a certain clinic are actually pregnant. In a random sample of 12 women, what is the probability that at least 10 are pregnant?

(Multiple Choice)

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Question 35

A random variable may be discrete or continuous, but not both.

(True/False)

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Question 36

Customer arrivals per unit of time would tend to follow a binomial distribution.

(True/False)

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Question 37

When you send out a resume, the probability of being called for an interview is .20. What is the probability that you get your first interview within the first five resumes that you send out?

(Multiple Choice)

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Question 38

If the probability of success is .30, what is the probability of obtaining the first success within the first five trials?

(Multiple Choice)

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Question 39

The expected value of a random variable X is 10 and the standard deviation is 2. The standard deviation of the random variable Y = 2X - 10 is:

(Multiple Choice)

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Question 40

Showing 21 - 40 of 126

On Saturday morning, calls arrive at TicketMaster at a rate of 108 calls per hour. What is the probability of fewer than three calls in a randomly chosen minute?

Which probability model is most nearly appropriate to describe the number of burned-out fluorescent tubes in a classroom with 12 fluorescent tubes, assuming a constant probability of a burned-out tube?

The expected value of a discrete random variable E(X) is the sum of all X values weighted by their respective probabilities.

Calculating the probability of getting three aces in a hand of five cards dealt from a deck of 52 cards would require the use of a hypergeometric distribution.

The binomial distribution is symmetrical when:

A stock portfolio consists of two stocks X and Y. Their daily closing prices are correlated random variables with variances σ_X² = 3.51 and σ_Y² = 5.22, and covariance σ_XY = -1.55. What is the standard deviation of the sum of the closing prices of these two stocks?

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, its mean is:

A project has 3 independent stages that must be completed in sequence. The time to complete each stage is a random variable. The standard deviations of the completion times for the stages are σ₁ = 5, σ₂ = 4, σ₃ = 6. The standard deviation of the overall project completion time is:

The probability that a visitor to an animal shelter will adopt a dog is .20. Out of nine visits, what is the probability that at least one dog will be adopted?

For which binomial distribution would a Poisson approximation be unacceptable?

The probability that a rental car will be stolen is 0.0004. If 3500 cars are rented, what is the approximate Poisson probability that 2 or fewer will be stolen?

The discrete random variable X is the number of passengers waiting at a bus stop. The table below shows the probability distribution for X. What is the expected value E(X) for this distribution? X 0 1 2 3 Total P(X) 20 40 30 10 1.00

Based on experience, 60 percent of the women who request a pregnancy test at a certain clinic are actually pregnant. In a random sample of 12 women, what is the probability that at least 10 are pregnant?

A random variable may be discrete or continuous, but not both.

Customer arrivals per unit of time would tend to follow a binomial distribution.

When you send out a resume, the probability of being called for an interview is .20. What is the probability that you get your first interview within the first five resumes that you send out?

If the probability of success is .30, what is the probability of obtaining the first success within the first five trials?

The expected value of a random variable X is 10 and the standard deviation is 2. The standard deviation of the random variable Y = 2X - 10 is:

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

Time Series Analysis

Chi-Square Tests

Nonparametric Tests

Quality Management

Filters

Exam 6: Discrete Probability Distributions

On Saturday morning, calls arrive at TicketMaster at a rate of 108 calls per hour. What is the probability of fewer than three calls in a randomly chosen minute?

Which probability model is most nearly appropriate to describe the number of burned-out fluorescent tubes in a classroom with 12 fluorescent tubes, assuming a constant probability of a burned-out tube?

The expected value of a discrete random variable E(X) is the sum of all X values weighted by their respective probabilities.

Calculating the probability of getting three aces in a hand of five cards dealt from a deck of 52 cards would require the use of a hypergeometric distribution.

The binomial distribution is symmetrical when:

A stock portfolio consists of two stocks X and Y. Their daily closing prices are correlated random variables with variances σX2 = 3.51 and σY2 = 5.22, and covariance σXY = -1.55. What is the standard deviation of the sum of the closing prices of these two stocks?

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, its mean is:

A project has 3 independent stages that must be completed in sequence. The time to complete each stage is a random variable. The standard deviations of the completion times for the stages are σ1 = 5, σ2 = 4, σ3 = 6. The standard deviation of the overall project completion time is:

The probability that a visitor to an animal shelter will adopt a dog is .20. Out of nine visits, what is the probability that at least one dog will be adopted?

For which binomial distribution would a Poisson approximation be unacceptable?

The probability that a rental car will be stolen is 0.0004. If 3500 cars are rented, what is the approximate Poisson probability that 2 or fewer will be stolen?

The discrete random variable X is the number of passengers waiting at a bus stop. The table below shows the probability distribution for X. What is the expected value E(X) for this distribution? X 0 1 2 3 Total P(X) 20 40 30 10 1.00

Based on experience, 60 percent of the women who request a pregnancy test at a certain clinic are actually pregnant. In a random sample of 12 women, what is the probability that at least 10 are pregnant?

A random variable may be discrete or continuous, but not both.

Customer arrivals per unit of time would tend to follow a binomial distribution.

When you send out a resume, the probability of being called for an interview is .20. What is the probability that you get your first interview within the first five resumes that you send out?

If the probability of success is .30, what is the probability of obtaining the first success within the first five trials?

The expected value of a random variable X is 10 and the standard deviation is 2. The standard deviation of the random variable Y = 2X - 10 is:

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

Time Series Analysis

Chi-Square Tests

Nonparametric Tests

Quality Management

Filters

A stock portfolio consists of two stocks X and Y. Their daily closing prices are correlated random variables with variances σ_X² = 3.51 and σ_Y² = 5.22, and covariance σ_XY = -1.55. What is the standard deviation of the sum of the closing prices of these two stocks?

A project has 3 independent stages that must be completed in sequence. The time to complete each stage is a random variable. The standard deviations of the completion times for the stages are σ₁ = 5, σ₂ = 4, σ₃ = 6. The standard deviation of the overall project completion time is: