Question 1

In constructing a confidence interval for the mean,the z distribution provides a result nearly identical to the t distribution when n is large.

Accepted Answer

A) True 
 B)False

Question 2

What is the approximate width of a 90 percent confidence interval for the true population proportion if there are 12 successes in a sample of 25?

Accepted Answer

A) ± 0.196 
B) ± 0.164 
C) ± 0.480 
D) ± 0.206 
A) ± 0.196 
B) ± 0.164 
C) ± 0.480 
D) ± 0.206

Question 3

In comparing estimators,the more efficient estimator will have a smaller standard error.

Accepted Answer

A) True 
 B)False

Question 4

The standard error of the mean decreases when

Accepted Answer

A) the sample size decreases. 
B) the standard deviation increases. 
C) the standard deviation decreases or n increases. 
D) the population size decreases. 
A) the sample size decreases. 
B) the standard deviation increases. 
C) the standard deviation decreases or n increases. 
D) the population size decreases.

Question 5

Sampling variation is not controllable by the statistician.

Accepted Answer

A) True 
 B)False

Question 6

For a sample of size 18,the critical values of chi-square for a 99 percent confidence interval for the population variance are

Accepted Answer

A) 6.262,27.49 
B) 5.697,35.72 
C) 5.629,26.12 
D) 7.261,25.00 
A) 6.262,27.49 
B) 5.697,35.72 
C) 5.629,26.12 
D) 7.261,25.00

Question 7

The efficiency of an estimator depends on the variance of the estimator's sampling distribution.

Accepted Answer

A) True 
 B)False

Question 8

The Central Limit Theorem (CLT)

Accepted Answer

A) applies only to samples from normal populations. 
B) applies to any population. 
C) applies best to populations that are skewed. 
D) applies only when μ and σ are known. 
A) applies only to samples from normal populations. 
B) applies to any population. 
C) applies best to populations that are skewed. 
D) applies only when μ and σ are known.

Question 9

The Central Limit Theorem says that a histogram of the sample means will have a bell shape,even if the population is skewed and the sample is small.

Accepted Answer

A) True 
 B)False

Question 10

To estimate the required sample size for a proportion,one method is to take a small pilot sample to estimate π and then apply the sample size formula.

Accepted Answer

A) True 
 B)False

Question 11

If a normal population has parameters μ = 40 and σ = 8,then for a sample size n = 4

Accepted Answer

A) the standard error of the sample mean is approximately 2. 
B) the standard error of the sample mean is approximately 4. 
C) the standard error of the sample mean is approximately 8. 
D) the standard error of the sample mean is approximately 10. 
A) the standard error of the sample mean is approximately 2. 
B) the standard error of the sample mean is approximately 4. 
C) the standard error of the sample mean is approximately 8. 
D) the standard error of the sample mean is approximately 10.

Question 12

The standard error of the sample proportion does not depend on the confidence level.

Accepted Answer

A) True 
 B)False

Question 13

The sample proportion is in the middle of the confidence interval for the population proportion

Accepted Answer

A) in any sample. 
B) only if the samples are large. 
C) only if π is not too far from 0.50. 
A) in any sample. 
B) only if the samples are large. 
C) only if π is not too far from 0.50.

Question 14

A consistent estimator for the mean

Accepted Answer

A) converges on the true parameter μ as the variance increases. 
B) converges on the true parameter μ as the sample size increases. 
C) consistently follows a normal distribution. 
D) is impossible to obtain using real sample data. 
A) converges on the true parameter μ as the variance increases. 
B) converges on the true parameter μ as the sample size increases. 
C) consistently follows a normal distribution. 
D) is impossible to obtain using real sample data.

Question 15

A financial institution wishes to estimate the mean balances owed by its credit card customers.The population standard deviation is $300.If a 99 percent confidence interval is used and an interval of ± $75 is desired,how many cardholders should be sampled?

Accepted Answer

A) 3,382 
B) 629 
C) 87 
D) 107 
A) 3,382 
B) 629 
C) 87 
D) 107

Question 16

Which of the following is not a characteristic of the t distribution?

Accepted Answer

A) It is a continuous distribution. 
B) It has a mean of 0. 
C) It is a symmetric distribution. 
D) It approaches z as degrees of freedom decrease. 
A) It is a continuous distribution. 
B) It has a mean of 0. 
C) It is a symmetric distribution. 
D) It approaches z as degrees of freedom decrease.

Question 17

As n increases,the width of the confidence interval will decrease,ceteris paribus.

Accepted Answer

A) True 
 B)False

Question 18

As long as the sample is more than one item,the standard error of the sample mean will be smaller than the standard deviation of the population.

Accepted Answer

A) True 
 B)False

Question 19

The Central Limit Theorem (CLT)says that,if n exceeds 30,the population will be normal.

Accepted Answer

A) True 
 B)False

Question 20

Which of the following statements is most nearly correct,other things being equal?

Accepted Answer

A) Using Student's t instead of z makes a confidence interval narrower. 
B) The table values of z and t are about the same when the mean is large. 
C) For a given confidence level,the z value is always smaller than the t value. 
D) Student's t is rarely used because it is more conservative to use z. 
A) Using Student's t instead of z makes a confidence interval narrower. 
B) The table values of z and t are about the same when the mean is large. 
C) For a given confidence level,the z value is always smaller than the t value. 
D) Student's t is rarely used because it is more conservative to use z.

In constructing a confidence interval for the mean,the z distribution provides a result nearly identical to the t distribution when n is large.

What is the approximate width of a 90 percent confidence interval for the true population proportion if there are 12 successes in a sample of 25?

In comparing estimators,the more efficient estimator will have a smaller standard error.

The standard error of the mean decreases when

Sampling variation is not controllable by the statistician.

For a sample of size 18,the critical values of chi-square for a 99 percent confidence interval for the population variance are

The efficiency of an estimator depends on the variance of the estimator's sampling distribution.

The Central Limit Theorem (CLT)

The Central Limit Theorem says that a histogram of the sample means will have a bell shape,even if the population is skewed and the sample is small.

To estimate the required sample size for a proportion,one method is to take a small pilot sample to estimate π and then apply the sample size formula.

If a normal population has parameters μ = 40 and σ = 8,then for a sample size n = 4

The standard error of the sample proportion does not depend on the confidence level.

The sample proportion is in the middle of the confidence interval for the population proportion

A consistent estimator for the mean

A financial institution wishes to estimate the mean balances owed by its credit card customers.The population standard deviation is $300.If a 99 percent confidence interval is used and an interval of ± $75 is desired,how many cardholders should be sampled?

Which of the following is not a characteristic of the t distribution?

As n increases,the width of the confidence interval will decrease,ceteris paribus.

As long as the sample is more than one item,the standard error of the sample mean will be smaller than the standard deviation of the population.

The Central Limit Theorem (CLT)says that,if n exceeds 30,the population will be normal.

Which of the following statements is most nearly correct,other things being equal?

Overview of Statistics

Data Collection

Describing Data Visually

Descriptive Statistics

Probability

Discrete Probability Distributions

Continuous Probability Distributions

One-Sample Hypothesis Tests

Two-Sample Hypothesis Tests

Analysis of Variance

Simple Regression

Multiple Regression

Chi-Square Tests

Filters

Exam 8: Sampling Distributions and Estimation

In constructing a confidence interval for the mean,the z distribution provides a result nearly identical to the t distribution when n is large.

What is the approximate width of a 90 percent confidence interval for the true population proportion if there are 12 successes in a sample of 25?

In comparing estimators,the more efficient estimator will have a smaller standard error.

The standard error of the mean decreases when

Sampling variation is not controllable by the statistician.

For a sample of size 18,the critical values of chi-square for a 99 percent confidence interval for the population variance are

The efficiency of an estimator depends on the variance of the estimator's sampling distribution.

The Central Limit Theorem (CLT)

The Central Limit Theorem says that a histogram of the sample means will have a bell shape,even if the population is skewed and the sample is small.

To estimate the required sample size for a proportion,one method is to take a small pilot sample to estimate π and then apply the sample size formula.

If a normal population has parameters μ = 40 and σ = 8,then for a sample size n = 4

The standard error of the sample proportion does not depend on the confidence level.

The sample proportion is in the middle of the confidence interval for the population proportion

A consistent estimator for the mean

A financial institution wishes to estimate the mean balances owed by its credit card customers.The population standard deviation is $300.If a 99 percent confidence interval is used and an interval of ± $75 is desired,how many cardholders should be sampled?

Which of the following is not a characteristic of the t distribution?

As n increases,the width of the confidence interval will decrease,ceteris paribus.

As long as the sample is more than one item,the standard error of the sample mean will be smaller than the standard deviation of the population.

The Central Limit Theorem (CLT)says that,if n exceeds 30,the population will be normal.

Which of the following statements is most nearly correct,other things being equal?

Overview of Statistics

Data Collection

Describing Data Visually

Descriptive Statistics

Probability

Discrete Probability Distributions

Continuous Probability Distributions

One-Sample Hypothesis Tests

Two-Sample Hypothesis Tests

Analysis of Variance

Simple Regression

Multiple Regression

Chi-Square Tests

Filters