Question 1

The upper limit of the 90% confidence interval for μ,where n = 81,= 70,and σ = 20,is 77.33.

Accepted Answer

A) True 
 B)False

Question 2

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 3

The upper limit of the 90% confidence interval for μ,where n = 64,= 70,and σ = 20,is 74.11

Accepted Answer

A) True 
 B)False

Question 4

The sample variance s2 is an unbiased estimator of the population variance σ2 when the denominator of s2 is

Accepted Answer

A) n + 1 
B) n 
C) n − 1 
D)    
A) n + 1 
B) n 
C) n − 1 
D)

Question 5

If the population standard deviation is guesstimated,and it turned out to be smaller than you assumed,then the sample size you calculated is ____________________ than it needs to be.

Accepted Answer

larger 
bi

Question 6

An electronics retailer is interested in studying the incomes of consumers in a particular area.The population standard deviation is known to be $1,000.What sample size would the researcher need to use for a 95% confidence interval if the difference between UCL and LCL should not be more than $100?

Accepted Answer

n = 1,537 (Note that

Question 7

A 95% confidence interval estimate for a population mean μ is determined to be 75 to 85.If the confidence level is reduced to 80%,the confidence interval for μ becomes wider.

Accepted Answer

A) True 
 B)False

Question 8

Suppose that a 95% confidence interval for μ is given by   .This notation means that,if we repeatedly draw samples of the same size from the same population,95% of the values of   will be such that μ would lie somewhere between   .

Accepted Answer

A) True 
 B)False

Question 9

An interval estimate is a range of values within which the actual value of the population parameter,such as μ,may fall.

Accepted Answer

A) True 
 B)False

Question 10

After constructing a confidence interval estimate for a population mean,you believe that the interval is useless because it is too wide.In order to correct this problem,you need to:

Accepted Answer

A) increase the sample size. 
B) increase the population standard deviation. 
C) increase the level of confidence. 
D) increase the sample mean. 
A) increase the sample size. 
B) increase the population standard deviation. 
C) increase the level of confidence. 
D) increase the sample mean.

Question 11

The width of a 95% confidence interval is 0.95.

Accepted Answer

A) True 
 B)False

Question 12

The sample mean   is a consistent estimator of the population mean μ.

Accepted Answer

A) True 
 B)False

Question 13

Which of the following conditions does not allow you to use the formula   to estimate μ?

Accepted Answer

A) Population is normally distributed and the population variance is known. 
B) Population is not normally distributed but n is large; population variance is known. 
C) Population has any distribution and n is any size. 
D) All of these choices allow you to use the formula. 
A) Population is normally distributed and the population variance is known. 
B) Population is not normally distributed but n is large; population variance is known. 
C) Population has any distribution and n is any size. 
D) All of these choices allow you to use the formula.

Question 14

Which of the following statements is correct?

Accepted Answer

A) The sample mean is an unbiased estimator of the population mean. 
B) The sample proportion is an unbiased estimator of the population proportion. 
C) The difference between two sample means is an unbiased estimator of the difference between two population means. 
D) All of these choices are true. 
A) The sample mean is an unbiased estimator of the population mean. 
B) The sample proportion is an unbiased estimator of the population proportion. 
C) The difference between two sample means is an unbiased estimator of the difference between two population means. 
D) All of these choices are true.

Question 15

A specific confidence interval obtained from data will always correctly estimate the population parameter.

Accepted Answer

A) True 
 B)False

Question 16

The term 1 − α refers to:

Accepted Answer

A) the probability that a confidence interval does not contain the population parameter. 
B) the confidence level. 
C) the level of unbiasedness. 
D) the level of consistency. 
A) the probability that a confidence interval does not contain the population parameter. 
B) the confidence level. 
C) the level of unbiasedness. 
D) the level of consistency.

Question 17

If there are two unbiased estimators of the same parameter,the one whose variance is smaller is said to be relatively more ____________________.

Accepted Answer

The answer of If there are two unbiased estimators of...

Question 18

Draw the sampling distribution of two unbiased estimators for μ,one of which is relatively efficient.

Accepted Answer

The answer of Draw the sampling distribution of two unbiased...

Question 19

If the population standard deviation is guesstimated,and it turned out to be larger than you assumed,then the sample size you calculated is ____________________ than it needs to be.

Accepted Answer

The answer of If the population standard deviation is guesstimated,and...

Question 20

The sample size needed to estimate a population mean to within 50 units was found to be 97.If the population standard deviation was 250,then the confidence level used was

Accepted Answer

A) 90% 
B) 95% 
C) 99% 
D) None of these choices. 
A) 90% 
B) 95% 
C) 99% 
D) None of these choices.

Exam 10: Introduction to Estimation

The upper limit of the 90% confidence interval for μ,where n = 81,= 70,and σ = 20,is 77.33.

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

The upper limit of the 90% confidence interval for μ,where n = 64,= 70,and σ = 20,is 74.11

The sample variance s2 is an unbiased estimator of the population variance σ2 when the denominator of s2 is

If the population standard deviation is guesstimated,and it turned out to be smaller than you assumed,then the sample size you calculated is ____________________ than it needs to be.

An electronics retailer is interested in studying the incomes of consumers in a particular area.The population standard deviation is known to be $1,000.What sample size would the researcher need to use for a 95% confidence interval if the difference between UCL and LCL should not be more than $100?

A 95% confidence interval estimate for a population mean μ is determined to be 75 to 85.If the confidence level is reduced to 80%,the confidence interval for μ becomes wider.

Suppose that a 95% confidence interval for μ is given by .This notation means that,if we repeatedly draw samples of the same size from the same population,95% of the values of will be such that μ would lie somewhere between .

An interval estimate is a range of values within which the actual value of the population parameter,such as μ,may fall.

After constructing a confidence interval estimate for a population mean,you believe that the interval is useless because it is too wide.In order to correct this problem,you need to:

The width of a 95% confidence interval is 0.95.

The sample mean is a consistent estimator of the population mean μ.

Which of the following conditions does not allow you to use the formula to estimate μ?

Which of the following statements is correct?

A specific confidence interval obtained from data will always correctly estimate the population parameter.

The term 1 − α refers to:

If there are two unbiased estimators of the same parameter,the one whose variance is smaller is said to be relatively more ____________________.

Draw the sampling distribution of two unbiased estimators for μ,one of which is relatively efficient.

If the population standard deviation is guesstimated,and it turned out to be larger than you assumed,then the sample size you calculated is ____________________ than it needs to be.

The sample size needed to estimate a population mean to within 50 units was found to be 97.If the population standard deviation was 250,then the confidence level used was

What Is Statistics

Graphical Descriptive Techniques 1

Graphical Descriptive Techniques 2

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

Model Building

Nonparametric Statistics

Time-Series Analytics and Forecasting

Statistical Process Control

Decision Analysis

Conclusion

Filters

The sample variance s² is an unbiased estimator of the population variance σ² when the denominator of s² is