Exam 7: Random Variables and Discrete Probability Distributions

Online Bankers An official from the securities commission estimates that 75% of all online bankers have profited from the use of insider information.Assume that 15 online bankers are selected at random from the commission's registry. -{Online Bankers Narrative} Find the probability that at most 10 have profited from insider information.

(Short Answer)

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Question 121

Retries The following table contains the probability distribution for X = the number of retries necessary to successfully transmit a 1024K data package through a double satellite media. -{Retries Narrative} What is the probability of no retries?

(Short Answer)

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Question 122

The mean of a discrete probability distribution for X is the sum of all possible values of X, divided by the number of possible values of X.

(True/False)

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Question 123

A motorcycle insurance company evaluates many numerical variables about a person before deciding on an appropriate rate for motorcycle insurance.The distance a person rides in a year is an example of a(n) ____________________ random variable.

(Short Answer)

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Question 124

The Poisson probability distribution is a continuous probability distribution.

(True/False)

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Question 125

Number of Birds Alana and Eva are sisters.Let X denote the number of birds that Alana may have in the next two years, and let Y denote the number of birds Eva may have during the same period.The marginal probability distributions of X and Y are shown below. -{Number of Birds Narrative} Determine the probability distribution of the random variable X + Y.

(Essay)

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Question 126

The expected value, E(X), of a binomial probability distribution with n trials and probability p of success is:

(Multiple Choice)

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Question 127

Unsafe Levels of Radioactivity The number of incidents at a nuclear power plant has a Poisson distribution with a mean of 6 incidents per year. -{Unsafe Levels of Radioactivity Narrative} Find the variance of the number of incidents in one year.

(Short Answer)

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Question 128

If X has a binomial distribution with n = 4 and p = 0.3, find the probability that X is at least one.

(Short Answer)

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Question 129

Sports Fans Suppose that past history shows that 5% of college students are sports fans.A sample of 10 students is to be selected. -{Sports Fans Narrative} Find the probability that at most 1 student is a sports fan.

(Short Answer)

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Question 130

Gym Visits Let X represent the number of times a student visits a gym in a one month period.Assume that the probability distribution of X is as follows: -{Gym Visits Narrative} What is the probability that the student visits the gym at most twice in a month?

(Short Answer)

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Question 131

Number of Birds Alana and Eva are sisters.Let X denote the number of birds that Alana may have in the next two years, and let Y denote the number of birds Eva may have during the same period.The marginal probability distributions of X and Y are shown below. -{Number of Birds Narrative} Verify that V(X + Y) = V(X) + V(Y).Did you expect this result? Why?

(Essay)

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Question 132

Elizabeth's Portfolio Elizabeth has decided to form a portfolio by putting 30% of her money into stock 1 and 70% into stock 2.She assumes that the expected returns will be 10% and 18%, respectively, and that the standard deviations will be 15% and 24%, respectively. -{Elizabeth's Portfolio Narrative} Describe what happens to the standard deviation of the portfolio returns when the coefficient of correlation decreases.

(Essay)

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Question 133

The probability of a success in a binomial experiment is denoted by ____________________.

(Short Answer)

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Question 134

Online Bankers An official from the securities commission estimates that 75% of all online bankers have profited from the use of insider information.Assume that 15 online bankers are selected at random from the commission's registry. -{Online Bankers Narrative} What is the expected number of Online bankers who have profited from the use of insider information?

(Short Answer)

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Question 135

The dean of students conducted a survey on campus.Grade point average (GPA) is an example of a(n) ____________________ random variable.

(Short Answer)

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Question 136

Golfing Store The joint probability distribution of variables X and Y is shown in the table below, where X is the number of drivers and Y is the number of putters sold daily in a small golfing store. -{Golfing Store Narrative} Calculate the expected values of X and Y.

(Short Answer)

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Question 137

If X and Y are independent variables, then their coefficient of correlation = 0.

(True/False)

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Question 138

Number of Motorcycles The probability distribution of a discrete random variable X is shown below, where X represents the number of motorcycles owned by a family. -{Number of Motorcycles Narrative} Apply the laws of expected value to find the following: a. E(X²) b. E(2X² + 5) c. E(X - 2)²

(Short Answer)

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Question 139

The probability P(X $\le$ x) is called a(n) ____________________ probability.The binomial table reports these probabilities.

(Short Answer)

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Question 140

Showing 121 - 140 of 274

Retries The following table contains the probability distribution for X = the number of retries necessary to successfully transmit a 1024K data package through a double satellite media. -{Retries Narrative} What is the probability of no retries?

The mean of a discrete probability distribution for X is the sum of all possible values of X, divided by the number of possible values of X.

A motorcycle insurance company evaluates many numerical variables about a person before deciding on an appropriate rate for motorcycle insurance.The distance a person rides in a year is an example of a(n) ____________________ random variable.

The Poisson probability distribution is a continuous probability distribution.

The expected value, E(X), of a binomial probability distribution with n trials and probability p of success is:

Unsafe Levels of Radioactivity The number of incidents at a nuclear power plant has a Poisson distribution with a mean of 6 incidents per year. -{Unsafe Levels of Radioactivity Narrative} Find the variance of the number of incidents in one year.

If X has a binomial distribution with n = 4 and p = 0.3, find the probability that X is at least one.

Sports Fans Suppose that past history shows that 5% of college students are sports fans.A sample of 10 students is to be selected. -{Sports Fans Narrative} Find the probability that at most 1 student is a sports fan.

Gym Visits Let X represent the number of times a student visits a gym in a one month period.Assume that the probability distribution of X is as follows: -{Gym Visits Narrative} What is the probability that the student visits the gym at most twice in a month?

The probability of a success in a binomial experiment is denoted by ____________________.

The dean of students conducted a survey on campus.Grade point average (GPA) is an example of a(n) ____________________ random variable.

Golfing Store The joint probability distribution of variables X and Y is shown in the table below, where X is the number of drivers and Y is the number of putters sold daily in a small golfing store. -{Golfing Store Narrative} Calculate the expected values of X and Y.

If X and Y are independent variables, then their coefficient of correlation = 0.

Number of Motorcycles The probability distribution of a discrete random variable X is shown below, where X represents the number of motorcycles owned by a family. -{Number of Motorcycles Narrative} Apply the laws of expected value to find the following: a. E(X²) b. E(2X² + 5) c. E(X - 2)²

The probability P(X $\le$ x) is called a(n) ____________________ probability.The binomial table reports these probabilities.

What Is Statistics

Graphical Descriptive Techniques I

Graphical Descriptive Techniques II

Numerical Descriptive Techniques

Data Collection and Sampling

Probability

Continuous Probability Distributions

Sampling Distributions

Introduction to Estimation

Introduction to Hypothesis Testing

Inference About a Population

Inference About Comparing Two Populations

Analysis of Variance

Chi-Squared Tests

Simple Linear Regression and Correlation

Multiple Regression

Filters

Exam 7: Random Variables and Discrete Probability Distributions

Retries The following table contains the probability distribution for X = the number of retries necessary to successfully transmit a 1024K data package through a double satellite media. -{Retries Narrative} What is the probability of no retries?

The mean of a discrete probability distribution for X is the sum of all possible values of X, divided by the number of possible values of X.

A motorcycle insurance company evaluates many numerical variables about a person before deciding on an appropriate rate for motorcycle insurance.The distance a person rides in a year is an example of a(n) ____________________ random variable.

The Poisson probability distribution is a continuous probability distribution.

The expected value, E(X), of a binomial probability distribution with n trials and probability p of success is:

Unsafe Levels of Radioactivity The number of incidents at a nuclear power plant has a Poisson distribution with a mean of 6 incidents per year. -{Unsafe Levels of Radioactivity Narrative} Find the variance of the number of incidents in one year.

If X has a binomial distribution with n = 4 and p = 0.3, find the probability that X is at least one.

Sports Fans Suppose that past history shows that 5% of college students are sports fans.A sample of 10 students is to be selected. -{Sports Fans Narrative} Find the probability that at most 1 student is a sports fan.

Gym Visits Let X represent the number of times a student visits a gym in a one month period.Assume that the probability distribution of X is as follows: -{Gym Visits Narrative} What is the probability that the student visits the gym at most twice in a month?

The probability of a success in a binomial experiment is denoted by ____________________.

The dean of students conducted a survey on campus.Grade point average (GPA) is an example of a(n) ____________________ random variable.

Golfing Store The joint probability distribution of variables X and Y is shown in the table below, where X is the number of drivers and Y is the number of putters sold daily in a small golfing store. -{Golfing Store Narrative} Calculate the expected values of X and Y.

If X and Y are independent variables, then their coefficient of correlation = 0.

Number of Motorcycles The probability distribution of a discrete random variable X is shown below, where X represents the number of motorcycles owned by a family. -{Number of Motorcycles Narrative} Apply the laws of expected value to find the following: a. E(X2) b. E(2X2 + 5) c. E(X - 2)2

The probability P(X ≤\le≤ x) is called a(n) ____________________ probability.The binomial table reports these probabilities.

What Is Statistics

Graphical Descriptive Techniques I

Graphical Descriptive Techniques II

Numerical Descriptive Techniques

Data Collection and Sampling

Probability

Continuous Probability Distributions

Sampling Distributions

Introduction to Estimation

Introduction to Hypothesis Testing

Inference About a Population

Inference About Comparing Two Populations

Analysis of Variance

Chi-Squared Tests

Simple Linear Regression and Correlation

Multiple Regression

Filters

Number of Motorcycles The probability distribution of a discrete random variable X is shown below, where X represents the number of motorcycles owned by a family. -{Number of Motorcycles Narrative} Apply the laws of expected value to find the following: a. E(X²) b. E(2X² + 5) c. E(X - 2)²

The probability P(X $\le$ x) is called a(n) ____________________ probability.The binomial table reports these probabilities.