Question 1

Doubling the population standard deviation $\sigma$ has the effect of doubling the width of the confidence interval estimate of $\mu$.

Accepted Answer

A) True 
 B)False

Question 2

Which of the following is not a part of the formula for constructing a confidence interval estimate of the population mean?

Accepted Answer

A)  A point estimate of the population mean. 
B)  The standard error of the sampling distribution of the sample mean. 
C)  The confidence level. 
D)  The value of the population mean. 
A)  A point estimate of the population mean. 
B)  The standard error of the sampling distribution of the sample mean. 
C)  The confidence level. 
D)  The value of the population mean.

Question 3

In determining the sample size n needed to estimate the population mean, n is higher if the population standard deviation$\sigma$ is higher.

Accepted Answer

A) True 
 B)False

Question 4

Time Spent Playing Computer Games
Suppose that the amount of time teenagers spend playing computer games per week is normally distributed with a standard deviation of 1.5 hours.A sample of 100 teenagers is selected at random, and the sample mean computed as 6.5 hours.
-{Time Spent Playing Computer Games Narrative} Determine the 95% confidence interval estimate of the population mean if the sample mean is changed to 8.5 hours.

Accepted Answer

LCL = 8.21

Question 5

The confidence interval estimate of the population mean is constructed around the sample mean.

Accepted Answer

A) True 
 B)False

Question 6

A 99% confidence interval estimate of the population mean $\mu$ can be interpreted to mean:

Accepted Answer

A)  if all possible sample are taken and confidence intervals created, 99% of them would include the true population mean somewhere within their interval. 
B)  we have 99% confidence that we have selected a sample whose interval does include the population mean. 
C)  we estimate that the population mean falls between the lower and upper confidence limits, and this type of estimator is correct 99% of the time. 
D)  All of these choices are true. 
A)  if all possible sample are taken and confidence intervals created, 99% of them would include the true population mean somewhere within their interval. 
B)  we have 99% confidence that we have selected a sample whose interval does include the population mean. 
C)  we estimate that the population mean falls between the lower and upper confidence limits, and this type of estimator is correct 99% of the time. 
D)  All of these choices are true.

Question 7

In developing an interval estimate for a population mean, a sample of 50 observations was used.The interval estimate was 19.  1.32.Had the sample size been 200 instead of 50, the interval estimate would have been:

Accepted Answer

A)  19.  .33 
B)  19.76   .66 
C)  19.76   5.28 
D)  None of these choices. 
A)  19.  .33 
B)  19.76   .66 
C)  19.76   5.28 
D)  None of these choices.

Question 8

A survey of 100 businesses revealed that the mean after-tax profit was $80,000.Assume the population standard deviation is $15,000:
a.
Determine the 95% confidence interval estimate of the mean after-tax profit for all businesses.
b.
Explain why you can use the confidence interval formula here, even though the population is not necessarily normal.

Accepted Answer

a.
LCL = $77,060 and UCL = $82

Question 9

The smallest number in a confidence interval is abbreviated by ____________________.

Accepted Answer

The answer of The smallest number in a confidence interval...

Question 10

Which of the following is an incorrect statement about a 90% confidence interval?

Accepted Answer

A)  If we repeatedly draw samples of the same size from the same population, 90% of the resulting confidence intervals will include $\mu$. 
B)  There is a 90% probability that the population mean $\mu$ will lie between the lower confidence limit (LCL) and the upper confidence limit (UCL). 
C)  We are 90% confident that our sample mean equals the population mean$\mu$. 
D)  90% of the population values will lie within the confidence interval. 
A)  If we repeatedly draw samples of the same size from the same population, 90% of the resulting confidence intervals will include $\mu$. 
B)  There is a 90% probability that the population mean $\mu$ will lie between the lower confidence limit (LCL) and the upper confidence limit (UCL). 
C)  We are 90% confident that our sample mean equals the population mean$\mu$. 
D)  90% of the population values will lie within the confidence interval.

Question 11

The librarian at the New York City Public Library has asked her assistant for an interval estimate of the mean number of books checked out each day.The assistant took a sample and found the mean to be 880 books.She provides the librarian with an interval estimate of between 790 and 970 books checked out per day.An efficient, unbiased point estimate of the number of books checked out each day at the New York City Public Library is:

Accepted Answer

A)  790 
B)  880 
C)  90 
D)  None of these choices. 
A)  790 
B)  880 
C)  90 
D)  None of these choices.

Question 12

Time Spent Playing Computer Games
Suppose that the amount of time teenagers spend playing computer games per week is normally distributed with a standard deviation of 1.5 hours.A sample of 100 teenagers is selected at random, and the sample mean computed as 6.5 hours.
-{Time Spent Playing Computer Games Narrative} Determine the 95% confidence interval estimate of the population mean if the population standard deviation is changed to 2.

Accepted Answer

LCL = 6.11

Question 13

____________________ estimators reflect the effects of larger sample sizes, but ____________________ estimators do not.

Accepted Answer

The answer of ____________________ estimators reflect the effects of larger...

Question 14

Draw a sampling distribution of an unbiased estimator for $\mu$.

Accepted Answer

The answer of Draw a sampling distribution of an unbiased...

Question 15

Suppose a 95% confidence interval for $\mu$ turns out to be (1,000, 2,100).What does it mean to be 95% confident?

Accepted Answer

A)  In repeated sampling, the population parameter would fall in the resulting interval 95% of the time. 
B)  95% of the observations in the entire population fall in the given interval. 
C)  95% of the observations in the sample fall in the given interval. 
D)  None of these choices. 
A)  In repeated sampling, the population parameter would fall in the resulting interval 95% of the time. 
B)  95% of the observations in the entire population fall in the given interval. 
C)  95% of the observations in the sample fall in the given interval. 
D)  None of these choices.

Question 16

Draw sampling distributions of a consistent estimator for $\mu$ where one sample mean is larger than the other.

Accepted Answer

The answer of Draw sampling distributions of a consistent estimator...

Question 17

When determining the sample size necessary for estimating the true population mean, which factor is not of our concern when sampling with replacement?

Accepted Answer

A)  The allowable or tolerable sampling error. 
B)  The level of confidence desired in the estimate. 
C)  The population standard deviation. 
D)  The population size. 
A)  The allowable or tolerable sampling error. 
B)  The level of confidence desired in the estimate. 
C)  The population standard deviation. 
D)  The population size.

Question 18

The term 1 - $\alpha$ refers to the probability that a confidence interval does not contain the population parameter.

Accepted Answer

A) True 
 B)False

Question 19

Increasing the value of 1- $\alpha$narrows a confidence interval.

Accepted Answer

A) True 
 B)False

Question 20

When determining the required sample size for a confidence interval, you need to know the population ____________________, the confidence ____________________, and the ____________________ on the error of estimation.

Accepted Answer

standard d

Doubling the population standard deviation $\sigma$ has the effect of doubling the width of the confidence interval estimate of $\mu$ .

Which of the following is not a part of the formula for constructing a confidence interval estimate of the population mean?

In determining the sample size n needed to estimate the population mean, n is higher if the population standard deviation $\sigma$ is higher.

The confidence interval estimate of the population mean is constructed around the sample mean.

A 99% confidence interval estimate of the population mean $\mu$ can be interpreted to mean:

In developing an interval estimate for a population mean, a sample of 50 observations was used.The interval estimate was 19.76 1.32.Had the sample size been 200 instead of 50, the interval estimate would have been:

The smallest number in a confidence interval is abbreviated by ____________________.

Which of the following is an incorrect statement about a 90% confidence interval?

estimators reflect the effects of larger sample sizes, but estimators do not.

Draw a sampling distribution of an unbiased estimator for $\mu$ .

Suppose a 95% confidence interval for $\mu$ turns out to be (1,000, 2,100).What does it mean to be 95% confident?

Draw sampling distributions of a consistent estimator for $\mu$ where one sample mean is larger than the other.

When determining the sample size necessary for estimating the true population mean, which factor is not of our concern when sampling with replacement?

The term 1 - $\alpha$ refers to the probability that a confidence interval does not contain the population parameter.

Increasing the value of 1- $\alpha$ narrows a confidence interval.

When determining the required sample size for a confidence interval, you need to know the population , the confidence , and the on the error of estimation.

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

Continuous Probability Distributions

Sampling Distributions

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 10: Introduction to Estimation

Doubling the population standard deviation σ\sigmaσ has the effect of doubling the width of the confidence interval estimate of μ\muμ .

Which of the following is not a part of the formula for constructing a confidence interval estimate of the population mean?

In determining the sample size n needed to estimate the population mean, n is higher if the population standard deviation σ\sigmaσ is higher.

The confidence interval estimate of the population mean is constructed around the sample mean.

A 99% confidence interval estimate of the population mean μ\muμ can be interpreted to mean:

In developing an interval estimate for a population mean, a sample of 50 observations was used.The interval estimate was 19.76 1.32.Had the sample size been 200 instead of 50, the interval estimate would have been:

The smallest number in a confidence interval is abbreviated by ____________________.

Which of the following is an incorrect statement about a 90% confidence interval?

____________________ estimators reflect the effects of larger sample sizes, but ____________________ estimators do not.

Draw a sampling distribution of an unbiased estimator for μ\muμ .

Suppose a 95% confidence interval for μ\muμ turns out to be (1,000, 2,100).What does it mean to be 95% confident?

Draw sampling distributions of a consistent estimator for μ\muμ where one sample mean is larger than the other.

When determining the sample size necessary for estimating the true population mean, which factor is not of our concern when sampling with replacement?

The term 1 - α\alphaα refers to the probability that a confidence interval does not contain the population parameter.

Increasing the value of 1- α\alphaα narrows a confidence interval.

When determining the required sample size for a confidence interval, you need to know the population ____________________, the confidence ____________________, and the ____________________ on the error of estimation.

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

Continuous Probability Distributions

Sampling Distributions

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

Doubling the population standard deviation $\sigma$ has the effect of doubling the width of the confidence interval estimate of $\mu$ .

In determining the sample size n needed to estimate the population mean, n is higher if the population standard deviation $\sigma$ is higher.

A 99% confidence interval estimate of the population mean $\mu$ can be interpreted to mean:

estimators reflect the effects of larger sample sizes, but estimators do not.

Draw a sampling distribution of an unbiased estimator for $\mu$ .

Suppose a 95% confidence interval for $\mu$ turns out to be (1,000, 2,100).What does it mean to be 95% confident?

Draw sampling distributions of a consistent estimator for $\mu$ where one sample mean is larger than the other.

The term 1 - $\alpha$ refers to the probability that a confidence interval does not contain the population parameter.

Increasing the value of 1- $\alpha$ narrows a confidence interval.

When determining the required sample size for a confidence interval, you need to know the population , the confidence , and the on the error of estimation.