In a hypothesis test for the population variance,the hypotheses are H0: $\sigma$2 = 30 vs.H1: $\sigma$2 < 30.If the sample size is 20 and the test is being carried out at the 5% level of significance,the null hypothesis is rejected if:

A) $\chi$2 2 > 10.851. C) $\chi$2 2 > 31.410. A) $\chi$2 2 > 10.851. C) $\chi$2 2 > 31.410.

Exam 12: Inference About a Population

Physicians A random sample of 200 physicians shows that there are 36 of them who make at least $400,000 a year. -{Physicians Narrative} Compute the p-value and explain how to use it to test the hypotheses.

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Question 121

The formula $\left( \frac { z _ { \alpha / 2 } \sqrt { \hat { p } ( 1 - \tilde { p } ) } } { B } \right) ^ { 2 }$ is used to find the ____________________ to estimate a population proportion.

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Question 122

Energy Drink Consumption A researcher at the University of Washington medical school believes that energy drink consumption may increase heart rate.Suppose it is known that heart rate (in beats per minute)is normally distributed with an average of 70 bpm for adults.A random sample of 25 adults was selected and it was found that their average heartbeat was 73 bpm after energy drink consumption,with a standard deviation of 7 bpm. -The chi-squared distribution can be used in constructing confidence intervals and carrying out hypothesis tests regarding the value of a population variance.

(True/False)

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Question 123

Energy Drink Consumption A researcher at the University of Washington medical school believes that energy drink consumption may increase heart rate.Suppose it is known that heart rate (in beats per minute)is normally distributed with an average of 70 bpm for adults.A random sample of 25 adults was selected and it was found that their average heartbeat was 73 bpm after energy drink consumption,with a standard deviation of 7 bpm. -The area to the right of a certain critical value on a chi-squared distribution is 0.025.For 5 degrees of freedom,the critical value is 11.143.

(True/False)

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Question 124

The test statistic used to test hypotheses about the population variance is given by $\chi$ ² = (n-1)s² / $\sigma$ ²,which is chi-squared distributed with n -1 degrees of freedom when the population random variable is normally distributed with variance equal to $\sigma$ ².

(True/False)

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Question 125

Healthy Foods In segmenting the frozen meal market in Spain,a food manufacturer uses health and diet consciousness as the segmentation variable.Four segments are developed and coded as follows: 1: Concermed about eating healthy faods 2: Concerned about weight 3: Concerned about health because of illnese 4: Unconcermed To distinguish between groups,surveys are conducted.On the basis of a questionnaire,people are categorized as belonging to one of these groups.A recent survey asked a random sample of 1,500 Spanish adults (20 and over)to complete the survey.Out of the 1,500 people surveyed,360 indicated that they are concerned about eating healthy foods.The most recent information available reveals that there are 40,256,000 Spanish adults who are 20 and over. -{Healthy Foods Narrative} Estimate with 95% confidence thee number of Spanish adults who classify themselves as concerned about eating healthy.

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Question 126

Which of the following is an example illustrating the use of variance?

(Multiple Choice)

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Question 127

To estimate ____________________ when the population size N is small,the confidence interval estimator is $\bar { x } \pm t _ { a / 2 } \cdot \frac { s } { \sqrt { n } } \sqrt { \frac { N - n } { N - 1 } }$ .

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Question 128

When a population is small,we must adjust the test statistic and interval estimator using the ____________________ population correction factor.

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Question 129

The formula $\left( \frac { z _ { \alpha / 2 } \sqrt { \hat { p } ( 1 - \tilde { p } ) } } { B } \right) ^ { 2 }$ is used to find the sample size needed to estimate a population proportion.In this formula,B represents the ____________________ on the error of estimation.

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Question 130

If the lower and upper confidence limits of the population mean $\mu$ ,using a sample of size 100,are 225 and 280,respectively,then the lower and upper confidence limits of the total of a population of size 3000 are respectively

(Multiple Choice)

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Question 131

Mystic Pizza Mystic Pizza in Mystic,Connecticut,advertises that they deliver your pizza within 15 minutes of placing an order or it is free.A sample of 25 customers is selected at random.The average delivery time in the sample was 13 minutes with a sample standard deviation of 4 minutes. -{Mystic Pizza Narrative} What is the required condition of the technique used in the previous question?

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Question 132

In estimating the population mean with the population standard deviation unknown,if the sample size is 16,there are 8 degrees of freedom.

(True/False)

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Question 133

In a hypothesis test for the population variance,the hypotheses are H₀: $\sigma$ ² = 30 vs.H₁: $\sigma$ ² < 30.If the sample size is 20 and the test is being carried out at the 5% level of significance,the null hypothesis is rejected if:

(Multiple Choice)

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Question 134

The t-test for a population mean is ____________________,meaning that if the population is nonnormal,the results of the test and confidence interval are still valid as long as the nonnormality is not extreme.

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Question 135

Pilots' Union Contract A union composed of several thousand pilots is preparing to vote on a new contract.A random sample of 500 pilots yielded 320 who planned to vote yes.It is believed that the new contract will receive more than 60% yes votes. -{Pilots' Union Contract Narrative} Compute the p-value for the test.

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Question 136

A life insurance representative believes that the mean age of people who buy their first life insurance plan is less than 35.To test his belief he takes a random sample of 15 customers who have just purchased their first life insurance.Their ages are 42,43,28,34,30,36,25,29,32,33,27,30,22,37,and 40.There is not enough evidence to say the data are nonnormal.Can we conclude at the 1% significance level that the insurance representative is correct?

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Question 137

Market segmentation separates consumers of a product into different groups in such a way that members of each group are similar to each other and there are differences between groups.

(True/False)

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Question 138

Sinus Drug A company claims that 10% of the users of a certain sinus drug experience drowsiness.In clinical studies of this sinus drug,81 of the 900 subjects experienced drowsiness -{Sinus Drug Narrative} Is there enough evidence at the 5% significance level to infer that the competitor is correct?

(Essay)

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Question 139

In market segmentation,if education is the segmentation variable of interest,then possible segments of the market include: some high school,high school graduates,some college,college or university graduates.

(True/False)

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Question 140

Showing 121 - 140 of 149

Exam 12: Inference About a Population

Physicians A random sample of 200 physicians shows that there are 36 of them who make at least $400,000 a year. -{Physicians Narrative} Compute the p-value and explain how to use it to test the hypotheses.

The formula (zα/2p^(1−p~)B)2\left( \frac { z _ { \alpha / 2 } \sqrt { \hat { p } ( 1 - \tilde { p } ) } } { B } \right) ^ { 2 }(Bzα/2​p^​(1−p~​)​​)2 is used to find the ____________________ to estimate a population proportion.

The test statistic used to test hypotheses about the population variance is given by χ\chiχ 2 = (n-1)s2 / σ\sigmaσ 2,which is chi-squared distributed with n -1 degrees of freedom when the population random variable is normally distributed with variance equal to σ\sigmaσ 2.

Which of the following is an example illustrating the use of variance?

To estimate ____________________ when the population size N is small,the confidence interval estimator is xˉ±ta/2⋅snN−nN−1\bar { x } \pm t _ { a / 2 } \cdot \frac { s } { \sqrt { n } } \sqrt { \frac { N - n } { N - 1 } }xˉ±ta/2​⋅n​s​N−1N−n​​ .

When a population is small,we must adjust the test statistic and interval estimator using the ____________________ population correction factor.

If the lower and upper confidence limits of the population mean μ\muμ ,using a sample of size 100,are 225 and 280,respectively,then the lower and upper confidence limits of the total of a population of size 3000 are respectively

In estimating the population mean with the population standard deviation unknown,if the sample size is 16,there are 8 degrees of freedom.

In a hypothesis test for the population variance,the hypotheses are H0: σ\sigmaσ 2 = 30 vs.H1: σ\sigmaσ 2 < 30.If the sample size is 20 and the test is being carried out at the 5% level of significance,the null hypothesis is rejected if:

The t-test for a population mean is ____________________,meaning that if the population is nonnormal,the results of the test and confidence interval are still valid as long as the nonnormality is not extreme.

Market segmentation separates consumers of a product into different groups in such a way that members of each group are similar to each other and there are differences between groups.

Sinus Drug A company claims that 10% of the users of a certain sinus drug experience drowsiness.In clinical studies of this sinus drug,81 of the 900 subjects experienced drowsiness -{Sinus Drug Narrative} Is there enough evidence at the 5% significance level to infer that the competitor is correct?

In market segmentation,if education is the segmentation variable of interest,then possible segments of the market include: some high school,high school graduates,some college,college or university graduates.

What Is Statistics

Graphical Descriptive Techniques I

Graphical Descriptive Techniques II

A: Numerical Descriptive Techniques

B: Numerical Descriptive Techniques

C: Numerical Descriptive Techniques

Data Collection and Sampling

Probability

A: Random Variables and Discrete Probability Distributions

B: Random Variables and Discrete Probability Distributions

Continuous Probability Distributions

Sampling Distributions

Introduction to Estimation

Introduction to Hypothesis Testing

Inference About Comparing Two Populations

Analysis of Variance

Chi-Squared Tests

A: Simple Linear Regression and Correlation

B: Simple Linear Regression and Correlation

Multiple Regression

Model Building

Nonparametric Statistics

Time-Series Analysis and Forecasting

Statistical Process Control

Decision Analysis

Conclusion

Filters

The formula $\left( \frac { z _ { \alpha / 2 } \sqrt { \hat { p } ( 1 - \tilde { p } ) } } { B } \right) ^ { 2 }$ is used to find the ____________________ to estimate a population proportion.

The test statistic used to test hypotheses about the population variance is given by $\chi$ ² = (n-1)s² / $\sigma$ ²,which is chi-squared distributed with n -1 degrees of freedom when the population random variable is normally distributed with variance equal to $\sigma$ ².

To estimate ____________________ when the population size N is small,the confidence interval estimator is $\bar { x } \pm t _ { a / 2 } \cdot \frac { s } { \sqrt { n } } \sqrt { \frac { N - n } { N - 1 } }$ .

If the lower and upper confidence limits of the population mean $\mu$ ,using a sample of size 100,are 225 and 280,respectively,then the lower and upper confidence limits of the total of a population of size 3000 are respectively

In a hypothesis test for the population variance,the hypotheses are H₀: $\sigma$ ² = 30 vs.H₁: $\sigma$ ² < 30.If the sample size is 20 and the test is being carried out at the 5% level of significance,the null hypothesis is rejected if: