Question 1

We distinguish between discrete and continuous random variables by noting whether the number of possible values is countable or uncountable.

Accepted Answer

A) True 
 B)False

Question 2

NARRBEGIN: Subway Waiting Time
Subway Waiting Time
At a subway station the waiting time for a subway is found to be uniformly distributed between 1 and 5 minutes.NARREND
-{Subway Waiting Time Narrative} What is the probability density function for this uniform distribution?

Accepted Answer

The answer of NARRBEGIN: Subway Waiting Time
Subway Waiting Time
At a...

Question 3

Which of the following is not true for an exponential distribution with parameter $\lambda$?

Accepted Answer

A) $\mu$ = 1/$\lambda$ 
B) $\sigma$ = 1/$\lambda$ 
C) The Y-intercept of f(x) is $\lambda$. 
D) All of these choices are true. 
A) $\mu$ = 1/$\lambda$ 
B) $\sigma$ = 1/$\lambda$ 
C) The Y-intercept of f(x) is $\lambda$. 
D) All of these choices are true.

Question 4

A(n) ____________________ random variable is one that assumes an uncountable number of possible values.

Accepted Answer

The answer of A(n) ____________________ random variable is one that...

Question 5

A random variable X is standardized by subtracting the mean and dividing by the variance.

Accepted Answer

A) True 
 B)False

Question 6

Which of the following distributions can take on negative values?

Accepted Answer

A) Student t 
B) $\chi$2 
C) F 
D) None of these choices. 
A) Student t 
B) $\chi$2 
C) F 
D) None of these choices.

Question 7

The Student t distribution with parameter v = 2 has a mean E(t) equal to:

Accepted Answer

A) 0 
B) 1 
C) 2 
D) None of these choices. 
A) 0 
B) 1 
C) 2 
D) None of these choices.

Question 8

We standardize a random variable by subtracting its ____________________ and dividing by its ____________________.

Accepted Answer

mean; stan

Question 9

Given that Z is a standard normal variable, the variance of Z:

Accepted Answer

A) is always greater than 2.0. 
B) is always greater than 1.0. 
C) is always equal to 1.0. 
D) cannot assume a specific value. 
A) is always greater than 2.0. 
B) is always greater than 1.0. 
C) is always equal to 1.0. 
D) cannot assume a specific value.

Question 10

As the ____________________ degrees of freedom increase, the mean of the F distribution approaches 1.

Accepted Answer

The answer of As the ____________________ degrees of freedom increase,...

Question 11

Suppose X has a chi-squared distribution with 10 degrees of freedom. The mean of X is:

Accepted Answer

A) 10 
B) 9 
C) 20 
D) None of these choices. 
A) 10 
B) 9 
C) 20 
D) None of these choices.

Question 12

NARRBEGIN: Diet
Diet
Researchers studying the effects of a new diet found that the weight loss over a one-month period by those on the diet was normally distributed with a mean of 10 pounds and a standard deviation of 5 pounds.NARREND
-Let X be a normally distributed random variable with a mean of 12 and a standard deviation of 1.5. What proportions of the values of X are:
a.less than 14
b.more than 8
c.between 10 and 13

Accepted Answer

a.0.9082
b

Question 13

If the random variable X is exponentially distributed, then the mean of X will be:

Accepted Answer

A) greater than the median. 
B) less than the median. 
C) equal to the median. 
D) Cannot tell; the answer depends on what $\lambda$ is. 
A) greater than the median. 
B) less than the median. 
C) equal to the median. 
D) Cannot tell; the answer depends on what $\lambda$ is.

Question 14

NARRBEGIN: Repair Time
Repair Time
The time it takes a technician to fix a telephone problem is exponentially distributed with a mean of 15 minutes.NARREND
-{Repair Time Narrative} What is the variance of the time it takes a technician to fix a telephone problem?

Accepted Answer

The answer of NARRBEGIN: Repair Time
Repair Time
The time it takes...

Question 15

Which of the following does not represent a continuous uniform random variable?

Accepted Answer

A) f(x) = 1/2 for x between -1 and 1, inclusive. 
B) f(x) = 10 for x between 0 and 1/10, inclusive. 
C) f(x) = 1/3 for x = 4, 5, 6. 
D) None of these choices represents a continuous uniform random variable. 
A) f(x) = 1/2 for x between -1 and 1, inclusive. 
B) f(x) = 10 for x between 0 and 1/10, inclusive. 
C) f(x) = 1/3 for x = 4, 5, 6. 
D) None of these choices represents a continuous uniform random variable.

Question 16

A continuous random variable X has a uniform distribution between 5 and 15 (inclusive), then the probability that X falls between 10 and 20 is 1.0.

Accepted Answer

A) True 
 B)False

Question 17

NARRBEGIN: Checking Accounts
Checking Accounts
A bank has determined that the monthly balances of the checking accounts of its customers are normally distributed with an average balance of $1,200 and a standard deviation of $250.NARREND
-{Checking Accounts Narrative} What proportion of customers have monthly balances less than $1,000?

Accepted Answer

The answer of NARRBEGIN: Checking Accounts
Checking Accounts
A bank has determined...

Question 18

NARRBEGIN: IT Graduates Salary
IT Graduates Salary
The recent average starting salary for new college graduates in IT systems is $47,500. Assume salaries are normally distributed with a standard deviation of $4,500.NARREND
-{IT Graduates Salary Narrative} What is the cutoff for the bottom 5% of the salaries?

Accepted Answer

The answer of NARRBEGIN: IT Graduates Salary
IT Graduates Salary
The recent...

Question 19

For a continuous random variable, the probability for each individual value of X is ____________________.

Accepted Answer

The answer of For a continuous random variable, the probability...

Question 20

The y-intercept of the density function for an exponential distribution with parameter 10 is ____________________.

Accepted Answer

The answer of The y-intercept of the density function for...

We distinguish between discrete and continuous random variables by noting whether the number of possible values is countable or uncountable.

NARRBEGIN: Subway Waiting Time Subway Waiting Time At a subway station the waiting time for a subway is found to be uniformly distributed between 1 and 5 minutes.NARREND -{Subway Waiting Time Narrative} What is the probability density function for this uniform distribution?

Which of the following is not true for an exponential distribution with parameter $\lambda$ ?

A(n) ____________________ random variable is one that assumes an uncountable number of possible values.

A random variable X is standardized by subtracting the mean and dividing by the variance.

Which of the following distributions can take on negative values?

The Student t distribution with parameter v = 2 has a mean E(t) equal to:

We standardize a random variable by subtracting its and dividing by its .

Given that Z is a standard normal variable, the variance of Z:

As the ____________________ degrees of freedom increase, the mean of the F distribution approaches 1.

Suppose X has a chi-squared distribution with 10 degrees of freedom. The mean of X is:

If the random variable X is exponentially distributed, then the mean of X will be:

NARRBEGIN: Repair Time Repair Time The time it takes a technician to fix a telephone problem is exponentially distributed with a mean of 15 minutes.NARREND -{Repair Time Narrative} What is the variance of the time it takes a technician to fix a telephone problem?

Which of the following does not represent a continuous uniform random variable?

A continuous random variable X has a uniform distribution between 5 and 15 (inclusive), then the probability that X falls between 10 and 20 is 1.0.

For a continuous random variable, the probability for each individual value of X is ____________________.

The y-intercept of the density function for an exponential distribution with parameter 10 is ____________________.

What Is Statistics

Graphical Descriptive Techniques I

Graphical Descriptive Techniques II

Numerical Descriptive Techniques

Data Collection and Sampling

Probability

Random Variables and Discrete 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 Optional

Simple Linear Regression and Correlation

Multiple Regression

Filters

Exam 8: Continuous Probability Distributions

We distinguish between discrete and continuous random variables by noting whether the number of possible values is countable or uncountable.

NARRBEGIN: Subway Waiting Time Subway Waiting Time At a subway station the waiting time for a subway is found to be uniformly distributed between 1 and 5 minutes.NARREND -{Subway Waiting Time Narrative} What is the probability density function for this uniform distribution?

Which of the following is not true for an exponential distribution with parameter λ\lambdaλ ?

A(n) ____________________ random variable is one that assumes an uncountable number of possible values.

A random variable X is standardized by subtracting the mean and dividing by the variance.

Which of the following distributions can take on negative values?

The Student t distribution with parameter v = 2 has a mean E(t) equal to:

We standardize a random variable by subtracting its ____________________ and dividing by its ____________________.

Given that Z is a standard normal variable, the variance of Z:

As the ____________________ degrees of freedom increase, the mean of the F distribution approaches 1.

Suppose X has a chi-squared distribution with 10 degrees of freedom. The mean of X is:

If the random variable X is exponentially distributed, then the mean of X will be:

NARRBEGIN: Repair Time Repair Time The time it takes a technician to fix a telephone problem is exponentially distributed with a mean of 15 minutes.NARREND -{Repair Time Narrative} What is the variance of the time it takes a technician to fix a telephone problem?

Which of the following does not represent a continuous uniform random variable?

A continuous random variable X has a uniform distribution between 5 and 15 (inclusive), then the probability that X falls between 10 and 20 is 1.0.

For a continuous random variable, the probability for each individual value of X is ____________________.

The y-intercept of the density function for an exponential distribution with parameter 10 is ____________________.

What Is Statistics

Graphical Descriptive Techniques I

Graphical Descriptive Techniques II

Numerical Descriptive Techniques

Data Collection and Sampling

Probability

Random Variables and Discrete 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 Optional

Simple Linear Regression and Correlation

Multiple Regression

Filters

Which of the following is not true for an exponential distribution with parameter $\lambda$ ?

We standardize a random variable by subtracting its and dividing by its .