Question 1

If the random variable X is exponentially distributed with parameter $\lambda$ = 5, then the variance of X, $\sigma$2 = V(X) = 0.04.

Accepted Answer

A) True 
 B)False

Question 2

Calculus Scores
Scores of high school students on a national calculus exam were normally distributed with a mean of 86 and a standard deviation of 4.(Total possible points = 100.)
-{Calculus Scores Narrative} What is the probability that a randomly selected student will have a score of 94 or lower?

Accepted Answer

The answer of Calculus Scores
Scores of high school students on...

Question 3

What proportion of the data from a normal distribution is within two standard deviations from the mean?

Accepted Answer

A)  0.3413 
B)  0.4772 
C)  0.6826 
D)  0.9544 
A)  0.3413 
B)  0.4772 
C)  0.6826 
D)  0.9544

Question 4

Suppose X has an exponential distribution with mean 2.Find f(x).

Accepted Answer

f(x) = 0.5

Question 5

Truck Salesman
A used truck salesman in a small town states that, on the average, it takes him 5 days to sell a truck.Assume that the probability distribution of the length of time between sales is exponentially distributed.
-{Truck Salesman Narrative} What is the probability that he will have to wait at least 8 days before making another sale?

Accepted Answer

0.2019 (No

Question 6

The probability that a standard normal random variable Z is less than -3.5 is approximately 0.

Accepted Answer

A) True 
 B)False

Question 7

Given that Z is a standard normal random variable, a negative value of Z indicates that the standard deviation of Z is negative.

Accepted Answer

A) True 
 B)False

Question 8

Waiting Time
The length of time patients must wait to see a doctor at an emergency room in a large hospital has a uniform distribution between 40 minutes and 3 hours.
-{Waiting Time Narrative} What is the probability that a patient would have to wait between one and two hours?

Accepted Answer

The answer of Waiting Time
The length of time patients must...

Question 9

If a point y lies outside the range of the possible values of a random variable X, then f(y) must equal zero.

Accepted Answer

A) True 
 B)False

Question 10

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

Accepted Answer

A) True 
 B)False

Question 11

A continuous random variable X has a uniform distribution between 10 and 20 (inclusive), then the probability that X falls between 12 and 15 is 0.30.

Accepted Answer

A) True 
 B)False

Question 12

If the random variable X is exponentially distributed with parameter$\lambda$ = 1.5, then the probability P(2$\le$ X $\le$ 4), up to 4 decimal places, is

Accepted Answer

A)  0.6667 
B)  0.0473 
C)  0.5000 
D)  0.2500 
A)  0.6667 
B)  0.0473 
C)  0.5000 
D)  0.2500

Question 13

Suppose X has an F distribution.Which of the following is true?

Accepted Answer

A)  f(x) is symmetrical. 
B)  All the values of X are non-negative. 
C)  The mean of X is zero. 
D)  All of these choices. 
A)  f(x) is symmetrical. 
B)  All the values of X are non-negative. 
C)  The mean of X is zero. 
D)  All of these choices.

Question 14

What happens to the shape, mean, and variance of a c2 distribution as the degrees of freedom increase?

Accepted Answer

The shape becomes le

Question 15

Phone Orders
The L.L.Bean catalog department that receives the majority of its orders by telephone conducted a study to determine how long customers were willing to wait on hold before ordering a product.The length of time was found to be a random variable best approximated by an exponential distribution with a mean equal to 3 minutes.
-{Phone Orders Narrative} Find the waiting time at which only 10% of the customers will continue to hold.

Accepted Answer

P(X > x) =

Question 16

Use the F table to find the following values of F.
a.
F.01,12,20
b.
F.05,20,40
c.
F.025,5,15
d.
F.01,8,30

Accepted Answer

a.
3.23
b.

Question 17

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 18

Suppose X is a continuous random variable for X between a and b.Then its probability ____________________ function must non-negative for all values of X between a and

Accepted Answer

The answer of Suppose X is a continuous random variable...

Question 19

The probability that Z is less than -2 is the same as one minus the probability that Z is greater than +2.

Accepted Answer

A) True 
 B)False

Question 20

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.
-{IT Graduates Salary Narrative} What is the probability of a new graduate receiving a salary between $45,000 and $50,000?

Accepted Answer

The answer of IT Graduates Salary
The recent average starting salary...

If the random variable X is exponentially distributed with parameter $\lambda$ = 5, then the variance of X, $\sigma$ ² = V(X) = 0.04.

Calculus Scores Scores of high school students on a national calculus exam were normally distributed with a mean of 86 and a standard deviation of 4.(Total possible points = 100.) -{Calculus Scores Narrative} What is the probability that a randomly selected student will have a score of 94 or lower?

What proportion of the data from a normal distribution is within two standard deviations from the mean?

Suppose X has an exponential distribution with mean 2.Find f(x).

The probability that a standard normal random variable Z is less than -3.5 is approximately 0.

Given that Z is a standard normal random variable, a negative value of Z indicates that the standard deviation of Z is negative.

Waiting Time The length of time patients must wait to see a doctor at an emergency room in a large hospital has a uniform distribution between 40 minutes and 3 hours. -{Waiting Time Narrative} What is the probability that a patient would have to wait between one and two hours?

If a point y lies outside the range of the possible values of a random variable X, then f(y) must equal zero.

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

A continuous random variable X has a uniform distribution between 10 and 20 (inclusive), then the probability that X falls between 12 and 15 is 0.30.

If the random variable X is exponentially distributed with parameter $\lambda$ = 1.5, then the probability P(2 $\le$ X $\le$ 4), up to 4 decimal places, is

Suppose X has an F distribution.Which of the following is true?

What happens to the shape, mean, and variance of a c² distribution as the degrees of freedom increase?

Use the F table to find the following values of F. a. F_.01,12,20 b. F_.05,20,40 c. F_.025,5,15 d. F_.01,8,30

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

Suppose X is a continuous random variable for X between a and b.Then its probability ____________________ function must non-negative for all values of X between a and

The probability that Z is less than -2 is the same as one minus the probability that Z is greater than +2.

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

Simple Linear Regression and Correlation

Multiple Regression

Filters

Exam 8: Continuous Probability Distributions

If the random variable X is exponentially distributed with parameter λ\lambdaλ = 5, then the variance of X, σ\sigmaσ 2 = V(X) = 0.04.

Calculus Scores Scores of high school students on a national calculus exam were normally distributed with a mean of 86 and a standard deviation of 4.(Total possible points = 100.) -{Calculus Scores Narrative} What is the probability that a randomly selected student will have a score of 94 or lower?

What proportion of the data from a normal distribution is within two standard deviations from the mean?

Suppose X has an exponential distribution with mean 2.Find f(x).

The probability that a standard normal random variable Z is less than -3.5 is approximately 0.

Given that Z is a standard normal random variable, a negative value of Z indicates that the standard deviation of Z is negative.

Waiting Time The length of time patients must wait to see a doctor at an emergency room in a large hospital has a uniform distribution between 40 minutes and 3 hours. -{Waiting Time Narrative} What is the probability that a patient would have to wait between one and two hours?

If a point y lies outside the range of the possible values of a random variable X, then f(y) must equal zero.

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

A continuous random variable X has a uniform distribution between 10 and 20 (inclusive), then the probability that X falls between 12 and 15 is 0.30.

If the random variable X is exponentially distributed with parameter λ\lambdaλ = 1.5, then the probability P(2 ≤\le≤ X ≤\le≤ 4), up to 4 decimal places, is

Suppose X has an F distribution.Which of the following is true?

What happens to the shape, mean, and variance of a c2 distribution as the degrees of freedom increase?

Use the F table to find the following values of F. a. F.01,12,20 b. F.05,20,40 c. F.025,5,15 d. F.01,8,30

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

Suppose X is a continuous random variable for X between a and b.Then its probability ____________________ function must non-negative for all values of X between a and

The probability that Z is less than -2 is the same as one minus the probability that Z is greater than +2.

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

Simple Linear Regression and Correlation

Multiple Regression

Filters

If the random variable X is exponentially distributed with parameter $\lambda$ = 5, then the variance of X, $\sigma$ ² = V(X) = 0.04.

If the random variable X is exponentially distributed with parameter $\lambda$ = 1.5, then the probability P(2 $\le$ X $\le$ 4), up to 4 decimal places, is

What happens to the shape, mean, and variance of a c² distribution as the degrees of freedom increase?

Use the F table to find the following values of F. a. F_.01,12,20 b. F_.05,20,40 c. F_.025,5,15 d. F_.01,8,30