Question 1

A standard normal distribution is a normal distribution with:

Accepted Answer

A) a mean of zero and a standard deviation of one. 
B) a mean of one and a standard deviation of zero. 
C) a mean always larger than the standard deviation. 
D) None of these choices. 
A) a mean of zero and a standard deviation of one. 
B) a mean of one and a standard deviation of zero. 
C) a mean always larger than the standard deviation. 
D) None of these choices. A

Question 2

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 cutoff for the top 3% of the salaries?

Accepted Answer

$55,960

Question 3

Which of the following is always true for all probability density functions of continuous random variables?

Accepted Answer

A) The probability at any single point is zero. 
B) They contain an uncountable number of possible values. 
C) The total area under the density function f(x)equals 1. 
D) All of these choices are true. 
A) The probability at any single point is zero. 
B) They contain an uncountable number of possible values. 
C) The total area under the density function f(x)equals 1. 
D) All of these choices are true. D

Question 4

Battery Life A certain brand of batteries has a lifetime that has a normal distribution with a mean of 3,750 hours and a standard deviation of 300 hours. {Battery Life Narrative} What proportion of these batteries will last between 3,800 and 4,100 hours?

Accepted Answer

The answer of Battery Life A certain brand of batteries...

Question 5

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 6

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 no more than one hour?

Accepted Answer

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

Question 7

The number of parameters for an F distribution is:

Accepted Answer

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

Question 8

Which of the following is not a characteristic for a normal distribution?

Accepted Answer

A) It is symmetrical. 
B) The mean is always zero. 
C) The mean, median, and mode are all equal. 
D) It is a bell-shaped distribution. 
A) It is symmetrical. 
B) The mean is always zero. 
C) The mean, median, and mode are all equal. 
D) It is a bell-shaped distribution.

Question 9

Let X represent weekly income expressed in dollars. Since there is no set upper limit, we cannot identify (and thus cannot count)all the possible values. Consequently, weekly income is regarded as a continuous random variable.

Accepted Answer

A) True 
 B)False

Question 10

P ( Z

Accepted Answer

The answer of P ( Z...

Question 11

A worker earns $16 per hour at a plant and is told that only 5% of all workers make a higher wage. If the wage is assumed to be normally distributed and the standard deviation of wage rates is $5 per hour, find the average wage for the plant workers per hour.

Accepted Answer

P ( X > 16)= .05 Þ (

Question 12

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. {Diet Narrative} What proportion of the dieters gained weight?

Accepted Answer

The answer of Diet Researchers studying the effects of a...

Question 13

A random variable X has a normal distribution with mean 132 and variance 36. If x = 120, its corresponding value of Z is 2.0.

Accepted Answer

A) True 
 B)False

Question 14

As the degrees of freedom approach infinity, the values of a Student t distribution approach those of a standard normal distribution.

Accepted Answer

A) True 
 B)False

Question 15

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 getting a starting salary in excess of $55,000?

Accepted Answer

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

Question 16

The value of an F distribution with v 1 = 6 and v 2 = 9 degrees of freedom such that the area to its right is 0.05 is 3.37.

Accepted Answer

A) True 
 B)False

Question 17

P ( Z > 1.9)= ____________________ P ( Z

Accepted Answer

The answer of P ( Z > 1.9)= ____________________ P...

Question 18

For values of degrees of freedom greater than 100, the X 2 distribution can be approximated by a(n)____________________ distribution.

Accepted Answer

Question 19

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

Question 20

Suppose you have a X 2 distribution with 20 degrees of freedom. 
 a. Find the mean. 
 b. Find the variance. 
 c. Find the standard deviation.

Accepted Answer

a. 20 
 b.

A standard normal distribution is a normal distribution with:

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 cutoff for the top 3% of the salaries?

Which of the following is always true for all probability density functions of continuous random variables?

Battery Life A certain brand of batteries has a lifetime that has a normal distribution with a mean of 3,750 hours and a standard deviation of 300 hours. {Battery Life Narrative} What proportion of these batteries will last between 3,800 and 4,100 hours?

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

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 no more than one hour?

The number of parameters for an F distribution is:

Which of the following is not a characteristic for a normal distribution?

Let X represent weekly income expressed in dollars. Since there is no set upper limit, we cannot identify (and thus cannot count)all the possible values. Consequently, weekly income is regarded as a continuous random variable.

P ( Z

A worker earns $16 per hour at a plant and is told that only 5% of all workers make a higher wage. If the wage is assumed to be normally distributed and the standard deviation of wage rates is $5 per hour, find the average wage for the plant workers per hour.

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. {Diet Narrative} What proportion of the dieters gained weight?

A random variable X has a normal distribution with mean 132 and variance 36. If x = 120, its corresponding value of Z is 2.0.

As the degrees of freedom approach infinity, the values of a Student t distribution approach those of a standard normal distribution.

The value of an F distribution with v ₁ = 6 and v ₂ = 9 degrees of freedom such that the area to its right is 0.05 is 3.37.

P ( Z > 1.9)= ____________________ P ( Z

For values of degrees of freedom greater than 100, the X ² distribution can be approximated by a(n)____________________ distribution.

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

Suppose you have a X ² distribution with 20 degrees of freedom. a. Find the mean. b. Find the variance. c. Find the standard deviation.

What Is Statistics

Graphical and Tabular Descriptive Techniques

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 Populat

Inference About Comparing Two Populat

Analysis of Variance

Chi-Squared Tests

Simple Linear Regression and Correlat

Multiple Regression

Review of Statistical Inference

Filters

Exam 7: Continuous Probability Distributions

A standard normal distribution is a normal distribution with:

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 cutoff for the top 3% of the salaries?

Which of the following is always true for all probability density functions of continuous random variables?

Battery Life A certain brand of batteries has a lifetime that has a normal distribution with a mean of 3,750 hours and a standard deviation of 300 hours. {Battery Life Narrative} What proportion of these batteries will last between 3,800 and 4,100 hours?

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

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 no more than one hour?

The number of parameters for an F distribution is:

Which of the following is not a characteristic for a normal distribution?

Let X represent weekly income expressed in dollars. Since there is no set upper limit, we cannot identify (and thus cannot count)all the possible values. Consequently, weekly income is regarded as a continuous random variable.

P ( Z

A worker earns $16 per hour at a plant and is told that only 5% of all workers make a higher wage. If the wage is assumed to be normally distributed and the standard deviation of wage rates is $5 per hour, find the average wage for the plant workers per hour.

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. {Diet Narrative} What proportion of the dieters gained weight?

A random variable X has a normal distribution with mean 132 and variance 36. If x = 120, its corresponding value of Z is 2.0.

As the degrees of freedom approach infinity, the values of a Student t distribution approach those of a standard normal distribution.

The value of an F distribution with v 1 = 6 and v 2 = 9 degrees of freedom such that the area to its right is 0.05 is 3.37.

P ( Z > 1.9)= ____________________ P ( Z

For values of degrees of freedom greater than 100, the X 2 distribution can be approximated by a(n)____________________ distribution.

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

Suppose you have a X 2 distribution with 20 degrees of freedom. a. Find the mean. b. Find the variance. c. Find the standard deviation.

What Is Statistics

Graphical and Tabular Descriptive Techniques

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 Populat

Inference About Comparing Two Populat

Analysis of Variance

Chi-Squared Tests

Simple Linear Regression and Correlat

Multiple Regression

Review of Statistical Inference

Filters

The value of an F distribution with v ₁ = 6 and v ₂ = 9 degrees of freedom such that the area to its right is 0.05 is 3.37.

For values of degrees of freedom greater than 100, the X ² distribution can be approximated by a(n)____________________ distribution.

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

Suppose you have a X ² distribution with 20 degrees of freedom. a. Find the mean. b. Find the variance. c. Find the standard deviation.