Exam 9: Estimation From Sample Data

For a selected month,the average kilowatt hours used for 49 residential customers showed that $\bar { x }$ is 1160 and s is 1085.Compute a 98% confidence interval estimate for the true mean. to

(Short Answer)

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Question 81

Explain whether the standard normal distribution or the t-distribution is employed under the following circumstances: A)Population: Not given; Sample size: 50; Population standard deviation: Given B)Population: Normal; Sample size: 16; Population standard deviation: Not given C)Population: Not given; Sample size: 40; Population standard deviation: Given D)Population: Normal; Sample size: 9; Population standard deviation: Given

(Essay)

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Question 82

With other factors unchanged,a lower confidence level will require a wider confidence interval.

(True/False)

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Question 83

Compute a 95 percent confidence interval for $\mu$ given a sample mean of 25,a sample size of 16,a sample standard deviation of 3.6,and a normal population. to

(Short Answer)

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Question 84

The national sales manager of Fast Grow Corp is working on next year's budget projections.He knows that the population standard deviation is $17.66.To estimate the daily per diem cost for outside sales people,he has taken a random sample of 36 individual expense accounts and found a mean of $90.29.The 91.08 percent confidence interval for the per diem expense is:

(Multiple Choice)

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Question 85

The difference between the sample statistic and actual value of the population parameter is referred to as the sampling error.

(True/False)

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Question 86

A 98% confidence interval estimate for a population mean $\mu$ is determined to be 75.38 to 86.52.If the confidence level is reduced to 90%,the confidence interval for $\mu$ :

(Multiple Choice)

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Question 87

Texas passed a law requiring drivers and passengers in the front seat to wear seat belts.In order to estimate the compliance with the law an unmarked car will operate in a selected county and the officer will observe whether or not seat belts are in use.The proportion complying, $\pi$ ,in the county is to be estimated by randomly selecting the cars to examine.A confidence coefficient of 0.98 is desired with the estimate,p,to be within 0.05 of the true proportion.How many cars are needed in this sample?

(Short Answer)

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Question 88

The larger the level of confidence used in constructing a confidence interval estimate of the population mean the:

(Multiple Choice)

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Question 89

Which of the following statements are correct?

(Multiple Choice)

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Question 90

With other factors unchanged,a higher confidence level will require a narrower confidence interval.

(True/False)

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Question 91

How large a sample of state employees should be taken if we want to estimate with 98% confidence the mean salary to within $2,000.The population standard deviation is assumed to be $10,500.

(Short Answer)

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Question 92

Because of the popularity of movies as an entertainment medium for college students,you plan to do a national study of the average cost of a movie ticket.If you assume that $\text { ? }$ = $0.50,what sample size would you have to take to be 95% confident that your estimate was within $0.25 of the true mean ticket prices?

(Multiple Choice)

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Question 93

The statistics $\bar { x }$ and p are unbiased estimators of the parameters and ,respectively.

(Essay)

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Question 94

The banking industry has suffered in recent years because of a high default rate on energy-related loans.The standard deviation is $10,000.How large a sample must you take from banking records to be 98% confident that your estimate for the amount of these defaults is within $1000 of the true mean loan amount?

(Multiple Choice)

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Question 95

If we want to cut the maximum likely error in half,we will have to double the sample size.

(True/False)

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Question 96

Texas passed a law requiring drivers and passengers in the front seat to wear seat belts.In order to estimate the compliance with the law an unmarked car will operate in a selected county and the officer will observe whether or not seat belts are in use.The proportion complying, $\pi$ ,in the county is to be estimated by randomly selecting the cars to examine.A confidence coefficient of 0.98 is desired with the estimate,p,to be within 0.05 of the true proportion.If an average number of cars passing the observation point per day is 12,000,how many cars are needed in this sample?

(Short Answer)

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Question 97

What do statisticians mean by the term accuracy?

(Essay)

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Question 98

In determining the necessary sample size in making an interval estimate for a population mean,it is necessary to decide on the maximum likely error that is acceptable.

(True/False)

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Question 99

An interval estimate is defined as:

(Multiple Choice)

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Question 100

Showing 81 - 100 of 150

For a selected month,the average kilowatt hours used for 49 residential customers showed that $\bar { x }$ is 1160 and s is 1085.Compute a 98% confidence interval estimate for the true mean. to

With other factors unchanged,a lower confidence level will require a wider confidence interval.

Compute a 95 percent confidence interval for $\mu$ given a sample mean of 25,a sample size of 16,a sample standard deviation of 3.6,and a normal population. to

The difference between the sample statistic and actual value of the population parameter is referred to as the sampling error.

A 98% confidence interval estimate for a population mean $\mu$ is determined to be 75.38 to 86.52.If the confidence level is reduced to 90%,the confidence interval for $\mu$ :

The larger the level of confidence used in constructing a confidence interval estimate of the population mean the:

Which of the following statements are correct?

With other factors unchanged,a higher confidence level will require a narrower confidence interval.

How large a sample of state employees should be taken if we want to estimate with 98% confidence the mean salary to within $2,000.The population standard deviation is assumed to be $10,500.

The statistics $\bar { x }$ and p are unbiased estimators of the parameters and ,respectively.

If we want to cut the maximum likely error in half,we will have to double the sample size.

What do statisticians mean by the term accuracy?

In determining the necessary sample size in making an interval estimate for a population mean,it is necessary to decide on the maximum likely error that is acceptable.

An interval estimate is defined as:

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

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Exam 9: Estimation From Sample Data

For a selected month,the average kilowatt hours used for 49 residential customers showed that xˉ\bar { x }xˉ is 1160 and s is 1085.Compute a 98% confidence interval estimate for the true mean. ____________________ to ____________________

With other factors unchanged,a lower confidence level will require a wider confidence interval.

Compute a 95 percent confidence interval for μ\muμ given a sample mean of 25,a sample size of 16,a sample standard deviation of 3.6,and a normal population. ____________________ to ____________________

The difference between the sample statistic and actual value of the population parameter is referred to as the sampling error.

A 98% confidence interval estimate for a population mean μ\muμ is determined to be 75.38 to 86.52.If the confidence level is reduced to 90%,the confidence interval for μ\muμ :

The larger the level of confidence used in constructing a confidence interval estimate of the population mean the:

Which of the following statements are correct?

With other factors unchanged,a higher confidence level will require a narrower confidence interval.

How large a sample of state employees should be taken if we want to estimate with 98% confidence the mean salary to within $2,000.The population standard deviation is assumed to be $10,500.

The statistics xˉ\bar { x }xˉ and p are unbiased estimators of the parameters ____________________ and ____________________,respectively.

If we want to cut the maximum likely error in half,we will have to double the sample size.

What do statisticians mean by the term accuracy?

In determining the necessary sample size in making an interval estimate for a population mean,it is necessary to decide on the maximum likely error that is acceptable.

An interval estimate is defined as:

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

For a selected month,the average kilowatt hours used for 49 residential customers showed that $\bar { x }$ is 1160 and s is 1085.Compute a 98% confidence interval estimate for the true mean. to

Compute a 95 percent confidence interval for $\mu$ given a sample mean of 25,a sample size of 16,a sample standard deviation of 3.6,and a normal population. to

A 98% confidence interval estimate for a population mean $\mu$ is determined to be 75.38 to 86.52.If the confidence level is reduced to 90%,the confidence interval for $\mu$ :

The statistics $\bar { x }$ and p are unbiased estimators of the parameters and ,respectively.