Exam 9: Estimation From Sample Data

A marketing class is engaged in a project to estimate the proportion of homes receiving both HBO and ShowTime cable service.The class plans to use a confidence coefficient of 0.95 and a maximum error of the estimate equal to 0.10.Determine the sample size for the class to use.

(Short Answer)

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Question 101

The Arkansas State Police wish to estimate the average mph being traveled on the Interstate Highways,which cross the state.If the estimate is to be within 8 mpg of the true mean with 98% confidence and the estimated standard deviation is 22 mph,how large a sample size must be taken?

(Multiple Choice)

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Question 102

A confidence interval is defined as:

(Multiple Choice)

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Question 103

A simple random sample of 10 students is selected from a large college.For the 10 students,the number of days each was absent during the last semester was to be 3,7,2,1,0,2,4,2,6,and 2.What is the point estimate for $\mu$ the mean number of days absent for the college's students?

(Short Answer)

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Question 104

The temperature readings for 20 winter days in Big Rapids,Michigan are normally distributed with a mean 5.5 degrees and a standard deviation of 1.5.Determine the 90% confidence interval estimate for the winter mean temperature. to

(Short Answer)

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Question 105

In order to estimate the average daily down time,a manufacturer randomly samples 40 days of production records and found a mean of 55.576 minutes and standard deviation of 77.9 minutes.An 80% confidence interval is:

(Multiple Choice)

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Question 106

The sample variance s² is an unbiased estimator of the population variance $? ^ { 2 }$ when the denominator of s² is:

(Multiple Choice)

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Question 107

The Student's t distribution has a mean of zero and the shape is determined by the number of degrees of freedom.

(True/False)

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Question 108

In surveying a simple random sample of 1000 assistant professors,we found that 573 of them felt they were underpaid by at least $3500.Based on these results,we have a 90% confidence that the proportion of the population of assistant professors who share this sentiment is between .548 and .598. Identify the accuracy of the sample result. The sample proportion would not differ from the actual population proportion by more than:

(Short Answer)

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Question 109

A 0.95 confidence coefficient is equivalent to a 5% confidence level.

(True/False)

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Question 110

Under what conditions is it appropriate to use the normal approximation to the binomial distribution in constructing the confidence interval for the population proportion $\pi$ ?

(Essay)

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Question 111

Your statistics instructor wants you to determine a confidence interval estimate for the mean test score for the next exam.In the past,the test scores have been normally distributed with a mean of 74.2 and a standard deviation of 30.9.A 95% confidence interval estimate if your class has 30 students is:

(Multiple Choice)

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Question 112

Briefly,what is the difference between a point estimate and an interval estimate for a population parameter?

(Essay)

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Question 113

Thirty-eight percent of a sample of 100 indicated that they used a company credit union because of lower interest rates for loans.Determine the 99% confidence interval estimate for the portion that use company credit unions due to lower loan rates. to

(Short Answer)

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Question 114

If a sample containing 12 observations is taken from a normally distributed population and a 99% confidence estimate for $\mu$ is needed,the appropriate t-score is:

(Multiple Choice)

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Question 115

The owner of a large shopping center is besieged with complaints concerning the shortage of parking space.He feels that the 1000 spaces are adequate.In an effort to address the problem,he obtains a sample of the average number of cars on the parking lot during prime hours.The sample of 40 has a mean of 952.Assume a population standard deviation of 396.The 95% confidence interval estimate for prime hour parking is:

(Multiple Choice)

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Question 116

As marketing manager for a very large discount building supply,you wish to know what proportion of your city's population conducted do-it-yourself home improvement projects during the past year.The national percentage is 62%; therefore,you decide to use this value in estimating sample size for a study to achieve 90% confidence with the estimate no more than 5% from the true proportion.If you know that the total city population is 30,000,what is the appropriate sample size?

(Short Answer)

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Question 117

You are interested in determining the average cost of a 3-minute telephone call to locations within the continental U.S.What sample size must you take to be 96% confident that the results will be within $.75 of the true mean cost per call? From the phone company,you have gotten an estimate of $\text { ? }$ = 7.71.

(Multiple Choice)

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Question 118

Delivery time by courier services is important to stock brokers.One such firm wishes to estimate the average time taken by couriers delivering negotiable securities in New York City.Specifically,the firm randomly samples 36 courier pickup and delivery times.The collected data,in minutes,represent the time between pickup and delivery.Suppose the population standard deviation is 0.3 minutes and the sample mean is 9.975.Find the sample mean and compute.A 90-percent confidence interval for the true mean delivery time, $\mu$ is:

(Multiple Choice)

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Question 119

A simple random sample of 10 students is selected from a large college.For the 10 students,the number of days each was absent during the last semester was to be 3,7,2,1,0,2,4,2,6,and 2.What is the point estimate for $σ ^ { 2 }$ ,the variance of the number of days absent for the college's students?

(Short Answer)

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Question 120

Showing 101 - 120 of 150

A marketing class is engaged in a project to estimate the proportion of homes receiving both HBO and ShowTime cable service.The class plans to use a confidence coefficient of 0.95 and a maximum error of the estimate equal to 0.10.Determine the sample size for the class to use.

The Arkansas State Police wish to estimate the average mph being traveled on the Interstate Highways,which cross the state.If the estimate is to be within 8 mpg of the true mean with 98% confidence and the estimated standard deviation is 22 mph,how large a sample size must be taken?

A confidence interval is defined as:

A simple random sample of 10 students is selected from a large college.For the 10 students,the number of days each was absent during the last semester was to be 3,7,2,1,0,2,4,2,6,and 2.What is the point estimate for $\mu$ the mean number of days absent for the college's students?

The temperature readings for 20 winter days in Big Rapids,Michigan are normally distributed with a mean 5.5 degrees and a standard deviation of 1.5.Determine the 90% confidence interval estimate for the winter mean temperature. to

In order to estimate the average daily down time,a manufacturer randomly samples 40 days of production records and found a mean of 55.576 minutes and standard deviation of 77.9 minutes.An 80% confidence interval is:

The sample variance s² is an unbiased estimator of the population variance $? ^ { 2 }$ when the denominator of s² is:

The Student's t distribution has a mean of zero and the shape is determined by the number of degrees of freedom.

A 0.95 confidence coefficient is equivalent to a 5% confidence level.

Under what conditions is it appropriate to use the normal approximation to the binomial distribution in constructing the confidence interval for the population proportion $\pi$ ?

Briefly,what is the difference between a point estimate and an interval estimate for a population parameter?

Thirty-eight percent of a sample of 100 indicated that they used a company credit union because of lower interest rates for loans.Determine the 99% confidence interval estimate for the portion that use company credit unions due to lower loan rates. to

If a sample containing 12 observations is taken from a normally distributed population and a 99% confidence estimate for $\mu$ is needed,the appropriate t-score is:

A simple random sample of 10 students is selected from a large college.For the 10 students,the number of days each was absent during the last semester was to be 3,7,2,1,0,2,4,2,6,and 2.What is the point estimate for $σ ^ { 2 }$ ,the variance of the number of days absent for the college's students?

A Preview of Business Statistics

Visual Description of Data

Statistical Description of Data

Data Collection and Sampling Methods

Probability: Review of Basic Concepts

Discrete Probability Distributions

Continuous Probability Distributions

Sampling Distributions

Hypothesis Tests Involving a Sample Mean or Proportion

Hypothesis Tests Involving Two Sample Means

Analysis of Variance Tests

Chi-Square Applications

Nonparametric Methods

Simple Linear Regression and Correlation

Multiple Regression and Correlation

Model Building

Models for Time Series and Forecasting

Decision Theory

Total Quality Management

Filters

Exam 9: Estimation From Sample Data

A marketing class is engaged in a project to estimate the proportion of homes receiving both HBO and ShowTime cable service.The class plans to use a confidence coefficient of 0.95 and a maximum error of the estimate equal to 0.10.Determine the sample size for the class to use.

The Arkansas State Police wish to estimate the average mph being traveled on the Interstate Highways,which cross the state.If the estimate is to be within 8 mpg of the true mean with 98% confidence and the estimated standard deviation is 22 mph,how large a sample size must be taken?

A confidence interval is defined as:

A simple random sample of 10 students is selected from a large college.For the 10 students,the number of days each was absent during the last semester was to be 3,7,2,1,0,2,4,2,6,and 2.What is the point estimate for μ\muμ the mean number of days absent for the college's students?

The temperature readings for 20 winter days in Big Rapids,Michigan are normally distributed with a mean 5.5 degrees and a standard deviation of 1.5.Determine the 90% confidence interval estimate for the winter mean temperature. ____________________ to ____________________

In order to estimate the average daily down time,a manufacturer randomly samples 40 days of production records and found a mean of 55.576 minutes and standard deviation of 77.9 minutes.An 80% confidence interval is:

The sample variance s 2 is an unbiased estimator of the population variance ?2? ^ { 2 }?2 when the denominator of s 2 is:

The Student's t distribution has a mean of zero and the shape is determined by the number of degrees of freedom.

A 0.95 confidence coefficient is equivalent to a 5% confidence level.

Under what conditions is it appropriate to use the normal approximation to the binomial distribution in constructing the confidence interval for the population proportion π\piπ ?

Briefly,what is the difference between a point estimate and an interval estimate for a population parameter?

Thirty-eight percent of a sample of 100 indicated that they used a company credit union because of lower interest rates for loans.Determine the 99% confidence interval estimate for the portion that use company credit unions due to lower loan rates. ____________________ to ____________________

If a sample containing 12 observations is taken from a normally distributed population and a 99% confidence estimate for μ\muμ is needed,the appropriate t-score is:

A Preview of Business Statistics

Visual Description of Data

Statistical Description of Data

Data Collection and Sampling Methods

Probability: Review of Basic Concepts

Discrete Probability Distributions

Continuous Probability Distributions

Sampling Distributions

Hypothesis Tests Involving a Sample Mean or Proportion

Hypothesis Tests Involving Two Sample Means

Analysis of Variance Tests

Chi-Square Applications

Nonparametric Methods

Simple Linear Regression and Correlation

Multiple Regression and Correlation

Model Building

Models for Time Series and Forecasting

Decision Theory

Total Quality Management

Filters

A simple random sample of 10 students is selected from a large college.For the 10 students,the number of days each was absent during the last semester was to be 3,7,2,1,0,2,4,2,6,and 2.What is the point estimate for $\mu$ the mean number of days absent for the college's students?

The temperature readings for 20 winter days in Big Rapids,Michigan are normally distributed with a mean 5.5 degrees and a standard deviation of 1.5.Determine the 90% confidence interval estimate for the winter mean temperature. to

The sample variance s² is an unbiased estimator of the population variance $? ^ { 2 }$ when the denominator of s² is:

Under what conditions is it appropriate to use the normal approximation to the binomial distribution in constructing the confidence interval for the population proportion $\pi$ ?

Thirty-eight percent of a sample of 100 indicated that they used a company credit union because of lower interest rates for loans.Determine the 99% confidence interval estimate for the portion that use company credit unions due to lower loan rates. to

If a sample containing 12 observations is taken from a normally distributed population and a 99% confidence estimate for $\mu$ is needed,the appropriate t-score is: