Question 1

An interval estimate is an interval that provides an upper and lower bound for a specific population parameter whose value is unknown.

Accepted Answer

A) True 
 B)False

Question 2

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
A regional CPA firm conducted an audit for a discount chain.One part of the audit involved developing an estimate for the mean dollar error in total charges that occur during the checkout process.They wish to develop a 90% confidence interval estimate for the population mean.A simple random sample of n = 20 is selected,with the following data (in dollars):
  
-Develop a 90% confidence interval estimate for the population mean.

Accepted Answer

@#IMG-DLM& ± t_α/2 ∙ s / @#IMG-DLM& = 0.77

Question 3

Confidence intervals for the population proportion are centered on the sample proportion.

Accepted Answer

A) True 
 B)False

Question 4

As the confidence level for a confidence interval increases,the width of the interval also increases.

Accepted Answer

A) True 
 B)False

Question 5

Consider the following random sample from a normal population: 14,10,13,16,12,18,15,and 11.What is the 95% confidence interval for the population variance?

Accepted Answer

A) 11.39 to 15.86 
B) 3.11 to 29.51 
C) 6.54 to 38.82 
D) 1.12 to 5.69 
A) 11.39 to 15.86 
B) 3.11 to 29.51 
C) 6.54 to 38.82 
D) 1.12 to 5.69

Question 6

The sample standard deviation s is an unbiased estimator of the population standard deviation σ.

Accepted Answer

A) True 
 B)False

Question 7

The bias of an estimator   
is equal to E(   
)- θ.

Accepted Answer

A) True 
 B)False

Question 8

When computing the confidence interval for the population proportion,the Student's t-distribution is used rather than the normal distribution.

Accepted Answer

A) True 
 B)False

Question 9

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
Let XS1U1B11S1U1B0,XS1U1B12S1U1B0,XS1U1B13S1U1B0,and XS1U1B14S1U1B0 be a random sample of observations from a population with mean μ and variance σS1U1P12S1S1P0.Consider the following two point estimators of μ:   
S1U1B11S1U1B0 = 0.10 XS1U1B11S1U1B0 + 0.20 XS1U1B12S1U1B0 + 0.40 XS1U1B13S1U1B0 + 0.30 XS1U1B14S1U1B0,and   
S1U1B12S1U1B0 = 0.25 XS1U1B11S1U1B0 + 0.25 XS1U1B12S1U1B0 + 0.30 XS1U1B13S1U1B0 + 0.20 XS1U1B14S1U1B0
-Raising in-state and out-of-state tuition is supposed to reduce the number of students in state supported universities.The registrar of a university wants to estimate the proportion P of students who are paying for out-of-state tuition on the installment plan (to later be compared with in-state installment plan payers).A random sample of 80 students who live out-of-state is taken and 50 of them pay tuition on the installment plan.Find a 99-percent confidence interval for P,based on these data.

Accepted Answer

@#IMG-DLM& ± z_.005 @#IMG-DLM& = .625 ± 2

Question 10

An unbiased estimator of a population parameter is an estimator whose variance is the same as the actual value of the population variance.

Accepted Answer

A) True 
 B)False

Question 11

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
A furniture mover calculates the actual weight as a proportion of estimated weight for a sample of 31 recent jobs.The sample mean is 1.13 and the sample standard deviation is 0.16.
-Assume that the population standard deviation is known to be 0.16.Calculate a 95% confidence interval for the population mean using the z table.

Accepted Answer

If σ is known to be 0.16,we ma

Question 12

The point estimator   
is said to be an unbiased estimator of θ if Var(   
)= Var(θ).

Accepted Answer

A) True 
 B)False

Question 13

In developing an interval estimate for a population mean,a sample of 40 observations was used.The interval estimate was 28.76 ± 1.48.Had the sample size been 160 instead of 40,the interval estimate would have been:

Accepted Answer

A) 28.76 ± 0.37 
B) 28.76 ± 0.74 
C) 28.76 ± 1.48 
D) 28.76 ± 2.96 
A) 28.76 ± 0.37 
B) 28.76 ± 0.74 
C) 28.76 ± 1.48 
D) 28.76 ± 2.96

Question 14

A mother who is interested in the true proportion of R-rated movies shown on pay TV by a cable system randomly selects 98 listings and finds 14 of them are R-rated movies.In her report to the subcommittee she wants to be 98% confident that the true proportion will be in an interval which she states.She has asked you to assist her by preparing a 98% confidence interval based on the data she collected.What should she report?

Accepted Answer

@#IMG-DLM& ± z_.01 @#IMG-DLM& = .1429 ± 2.

Question 15

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
Let XS1U1B11S1U1B0,XS1U1B12S1U1B0,XS1U1B13S1U1B0,and XS1U1B14S1U1B0 be a random sample of observations from a population with mean μ and variance σS1U1P12S1S1P0.Consider the following two point estimators of μ:   
S1U1B11S1U1B0 = 0.10 XS1U1B11S1U1B0 + 0.20 XS1U1B12S1U1B0 + 0.40 XS1U1B13S1U1B0 + 0.30 XS1U1B14S1U1B0,and   
S1U1B12S1U1B0 = 0.25 XS1U1B11S1U1B0 + 0.25 XS1U1B12S1U1B0 + 0.30 XS1U1B13S1U1B0 + 0.20 XS1U1B14S1U1B0
-Which estimator is more efficient,(   1)or (   2)? Explain in detail.

Accepted Answer

Var( @#IMG-DLM& ₁)= Var(0.10 X₁)+ Var(0.20 X₂)+ Var(0

Question 16

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
A school bus driver records the time (in minutes)it takes to commute to school for six days.Those results are: 25,22,17,20,15,and 10.Assuming the population is normally distributed,develop a 90% confidence interval for the population mean.
-What is the value of the sample standard deviation?

Accepted Answer

A) 4.88 
B) 4.25 
C) 5.34 
D) 3.64 
A) 4.88 
B) 4.25 
C) 5.34 
D) 3.64

Question 17

The 95% confidence interval for the population proportion P given a sample size n = 300 and sample proportion   = 0.2933 is calculated as:

Accepted Answer

A) 0.2933 ± 0.0515 
B) 0.2933 ± 0.0289 
C) 0.2933 ± 0.9200 
D) 0.2933 ± 0.8145 
A) 0.2933 ± 0.0515 
B) 0.2933 ± 0.0289 
C) 0.2933 ± 0.9200 
D) 0.2933 ± 0.8145

Question 18

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
From a random sample of 500 registered voters in Los Angeles,400 indicated that they would vote in favor of a proposed policy in an upcoming election.
-Calculate the width of the 90% confidence interval estimate for the population proportion in favor of this policy.

Accepted Answer

In this case,z_α/2 = z_0.05 = 1.645 Mar

Question 19

Which of the following statements is true?

Accepted Answer

A) If a sample has 16 observations and a 90% confidence estimate for μ is needed,the appropriate t-score is 1.753. 
B) If a sample has 16 observations and a 99% confidence estimate for μ is needed,the appropriate t-score is 2.602. 
C) If a sample has 20 observations and a 95% confidence estimate for μ is needed,the appropriate t-score is 1.729. 
D) If a sample has 20 observations and a 98% confidence estimate for μ is needed,the appropriate t-score is 2.093. 
A) If a sample has 16 observations and a 90% confidence estimate for μ is needed,the appropriate t-score is 1.753. 
B) If a sample has 16 observations and a 99% confidence estimate for μ is needed,the appropriate t-score is 2.602. 
C) If a sample has 20 observations and a 95% confidence estimate for μ is needed,the appropriate t-score is 1.729. 
D) If a sample has 20 observations and a 98% confidence estimate for μ is needed,the appropriate t-score is 2.093.

Question 20

The upper limit of 90% confidence interval for the population proportion P,given a sample size n = 300 and sample proportion   = 0.1833 is equal to:

Accepted Answer

A) 0.1466 
B) 0.1395 
C) 0.2271 
D) 0.2200 
A) 0.1466 
B) 0.1395 
C) 0.2271 
D) 0.2200

An interval estimate is an interval that provides an upper and lower bound for a specific population parameter whose value is unknown.

Confidence intervals for the population proportion are centered on the sample proportion.

As the confidence level for a confidence interval increases,the width of the interval also increases.

Consider the following random sample from a normal population: 14,10,13,16,12,18,15,and 11.What is the 95% confidence interval for the population variance?

The sample standard deviation s is an unbiased estimator of the population standard deviation σ.

The bias of an estimator is equal to E( )- θ.

When computing the confidence interval for the population proportion,the Student's t-distribution is used rather than the normal distribution.

An unbiased estimator of a population parameter is an estimator whose variance is the same as the actual value of the population variance.

The point estimator is said to be an unbiased estimator of θ if Var( )= Var(θ).

In developing an interval estimate for a population mean,a sample of 40 observations was used.The interval estimate was 28.76 ± 1.48.Had the sample size been 160 instead of 40,the interval estimate would have been:

The 95% confidence interval for the population proportion P given a sample size n = 300 and sample proportion = 0.2933 is calculated as:

Which of the following statements is true?

The upper limit of 90% confidence interval for the population proportion P,given a sample size n = 300 and sample proportion = 0.1833 is equal to:

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Describing Data: Numerical

Probability

Discrete Random Variables and Probability Distributions

Continuous Random Variables and Probability Distributions

Sampling and Sampling Distributions

Estimation: Additional Topics

Hypothesis Testing: Single Population

Hypothesis Testing: Additional Topics

Simple Regression

Multiple Regression

Additional Topics in Regression Analysis

Analysis of Categorical Data

Analysis of Variance

Time-Series Analysis and Forecasting

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Exam 7: Estimation: Single Population

An interval estimate is an interval that provides an upper and lower bound for a specific population parameter whose value is unknown.

Confidence intervals for the population proportion are centered on the sample proportion.

As the confidence level for a confidence interval increases,the width of the interval also increases.

Consider the following random sample from a normal population: 14,10,13,16,12,18,15,and 11.What is the 95% confidence interval for the population variance?

The sample standard deviation s is an unbiased estimator of the population standard deviation σ.

The bias of an estimator is equal to E( )- θ.

When computing the confidence interval for the population proportion,the Student's t-distribution is used rather than the normal distribution.

An unbiased estimator of a population parameter is an estimator whose variance is the same as the actual value of the population variance.

The point estimator is said to be an unbiased estimator of θ if Var( )= Var(θ).

In developing an interval estimate for a population mean,a sample of 40 observations was used.The interval estimate was 28.76 ± 1.48.Had the sample size been 160 instead of 40,the interval estimate would have been:

The 95% confidence interval for the population proportion P given a sample size n = 300 and sample proportion = 0.2933 is calculated as:

Which of the following statements is true?

The upper limit of 90% confidence interval for the population proportion P,given a sample size n = 300 and sample proportion = 0.1833 is equal to:

Describing Data: Graphical

Describing Data: Numerical

Probability

Discrete Random Variables and Probability Distributions

Continuous Random Variables and Probability Distributions

Sampling and Sampling Distributions

Estimation: Additional Topics

Hypothesis Testing: Single Population

Hypothesis Testing: Additional Topics

Simple Regression

Multiple Regression

Additional Topics in Regression Analysis

Analysis of Categorical Data

Analysis of Variance

Time-Series Analysis and Forecasting

Additional Topics in Sampling

Filters