The statistic (n - 1)s2 / $\sigma$2 has a chi-squared distribution with n - 1 degrees of freedom if:

A) the sample has a Student t-distribution with degrees of freedom equal to n- 1. B) the sample is normally distributed with variance equal to s2. C) the population is normally distributed with variance equal to $\sigma$2. D) All of these choices are true. A) the sample has a Student t-distribution with degrees of freedom equal to n- 1. B) the sample is normally distributed with variance equal to s2. C) the population is normally distributed with variance equal to $\sigma$2. D) All of these choices are true.

Exam 11: Inference About a Population

A random sample of 25 observations is selected from a normally distributed population. The sample variance is 10. In the 95% confidence interval for the population variance, the upper limit is:

(Multiple Choice)

4.9/5

(33)

Question 21

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.

(Short Answer)

4.9/5

(28)

Question 22

Applicants' Grades: The grades of a sample of 10 applicants, selected at random from a large population, are 71, 86, 75, 63, 92, 70, 81, 59, 80, and 90. -Compute the sample variance.

(Essay)

4.9/5

(24)

Question 23

The degrees of freedom for the test statistic for $\mu$ when $\sigma$ is unknown is:

(Multiple Choice)

4.8/5

(39)

Question 24

Because of the greater uncertainty, the t-statistic will display greater ____________________ than the z-statistic.

(Short Answer)

4.7/5

(48)

Question 25

Which of the following conditions is needed regarding the chi-squared test statistic for the test of variance?

(Multiple Choice)

4.9/5

(34)

Question 26

If a sample has 15 observations and a 95% confidence estimate for $\mu$ is needed, the appropriate value of t is 1.753.

(True/False)

4.8/5

(32)

Question 27

When the population standard deviation is unknown and the population is normal, the test statistic for testing hypotheses about $\mu$ is the -distribution with degrees of freedom.

(Short Answer)

4.8/5

(40)

Question 28

A condition of using the chi-squared test statistic for testing the variance is that the population random variable have a normal distribution.

(True/False)

4.8/5

(36)

Question 29

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?

(Essay)

4.8/5

(38)

Question 30

A robust estimator is one that is:

(Multiple Choice)

4.7/5

(30)

Question 31

The ____________________ confidence limit of the confidence interval estimator of the population variance is .

(Short Answer)

4.9/5

(40)

Question 32

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)

4.8/5

(44)

Question 33

A major electronics store chain is interested in estimating the average amount its credit card customers spent on their first visit to the chain's new store in the mall. Fifteen credit card accounts were randomly sampled and analyzed with the following results: = $50.50 and s² = 400. A 95% confidence interval for the average amount the credit card customers spent on their first visit to the chain's new store in the mall is:

(Multiple Choice)

4.8/5

(35)

Question 34

Applicants' Grades: The grades of a sample of 10 applicants, selected at random from a large population, are 71, 86, 75, 63, 92, 70, 81, 59, 80, and 90. -Construct a 90% confidence interval estimate for the population variance.

(Essay)

4.8/5

(35)

Question 35

In order to determine the p-value associated with hypothesis testing about the population mean $\mu$ , it is necessary to know the value of the test statistic.

(True/False)

4.7/5

(37)

Question 36

The t-statistic has two variables: the sample and the sample .

(Short Answer)

4.7/5

(46)

Question 37

The statistic (n - 1)s² / $\sigma$ ² has a chi-squared distribution with n - 1 degrees of freedom if:

(Multiple Choice)

4.8/5

(37)

Question 38

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 is normally distributed with variance equal to $\sigma$ ².

(True/False)

4.8/5

(39)

Question 39

The sales manager of a large multinational corporation is concerned that some salespersons perform very well and others quite poorly. To help analyze the problem he draws a random sample of 20 salespersons, determines their commission incomes (in thousands of dollars), and calculates the following statistics: = $37.2, and s = $7.8. Do these statistics provide sufficient evidence at the 5% significance level to conclude that the population variance exceeds $35 million²?

(Essay)

4.8/5

(35)

Question 40

Showing 21 - 40 of 75

A random sample of 25 observations is selected from a normally distributed population. The sample variance is 10. In the 95% confidence interval for the population variance, the upper limit is:

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.

Applicants' Grades: The grades of a sample of 10 applicants, selected at random from a large population, are 71, 86, 75, 63, 92, 70, 81, 59, 80, and 90. -Compute the sample variance.

The degrees of freedom for the test statistic for $\mu$ when $\sigma$ is unknown is:

Because of the greater uncertainty, the t-statistic will display greater ____________________ than the z-statistic.

Which of the following conditions is needed regarding the chi-squared test statistic for the test of variance?

If a sample has 15 observations and a 95% confidence estimate for $\mu$ is needed, the appropriate value of t is 1.753.

When the population standard deviation is unknown and the population is normal, the test statistic for testing hypotheses about $\mu$ is the -distribution with degrees of freedom.

A condition of using the chi-squared test statistic for testing the variance is that the population random variable have a normal distribution.

A robust estimator is one that is:

The ____________________ confidence limit of the confidence interval estimator of the population variance is .

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

Applicants' Grades: The grades of a sample of 10 applicants, selected at random from a large population, are 71, 86, 75, 63, 92, 70, 81, 59, 80, and 90. -Construct a 90% confidence interval estimate for the population variance.

In order to determine the p-value associated with hypothesis testing about the population mean $\mu$ , it is necessary to know the value of the test statistic.

The t-statistic has two variables: the sample and the sample .

The statistic (n - 1)s² / $\sigma$ ² has a chi-squared distribution with n - 1 degrees of freedom if:

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 is normally distributed with variance equal to $\sigma$ ².

What Is Statistics

Graphical and Tabular Descriptive Techniques

Numerical Descriptive Techniques

Data Collection and Sampling

Probability

Random Variables and Discrete Probability Distributions

Continuous Probability Distributions

Sampling Distributions

Introduction to Estimation

Introduction to Hypothesis Testing

Inference About Comparing Two Populations, Part 1

Inference About Comparing Two Populations, Part 2

Analysis of Variance

Chi-Squared Tests

Simple Linear Regression and Correlation

Multiple Regression

Review of Statistical Inference

Filters

Exam 11: Inference About a Population

A random sample of 25 observations is selected from a normally distributed population. The sample variance is 10. In the 95% confidence interval for the population variance, the upper limit is:

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.

Applicants' Grades: The grades of a sample of 10 applicants, selected at random from a large population, are 71, 86, 75, 63, 92, 70, 81, 59, 80, and 90. -Compute the sample variance.

The degrees of freedom for the test statistic for μ\muμ when σ\sigmaσ is unknown is:

Because of the greater uncertainty, the t-statistic will display greater ____________________ than the z-statistic.

Which of the following conditions is needed regarding the chi-squared test statistic for the test of variance?

If a sample has 15 observations and a 95% confidence estimate for μ\muμ is needed, the appropriate value of t is 1.753.

When the population standard deviation is unknown and the population is normal, the test statistic for testing hypotheses about μ\muμ is the ____________________-distribution with ____________________ degrees of freedom.

A condition of using the chi-squared test statistic for testing the variance is that the population random variable have a normal distribution.

A robust estimator is one that is:

The ____________________ confidence limit of the confidence interval estimator of the population variance is .

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

Applicants' Grades: The grades of a sample of 10 applicants, selected at random from a large population, are 71, 86, 75, 63, 92, 70, 81, 59, 80, and 90. -Construct a 90% confidence interval estimate for the population variance.

In order to determine the p-value associated with hypothesis testing about the population mean μ\muμ , it is necessary to know the value of the test statistic.

The t-statistic has two variables: the sample ____________________ and the sample ____________________.

The statistic (n - 1)s2 / σ\sigmaσ 2 has a chi-squared distribution with n - 1 degrees of freedom if:

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 is normally distributed with variance equal to σ\sigmaσ 2.

What Is Statistics

Graphical and Tabular Descriptive Techniques

Numerical Descriptive Techniques

Data Collection and Sampling

Probability

Random Variables and Discrete Probability Distributions

Continuous Probability Distributions

Sampling Distributions

Introduction to Estimation

Introduction to Hypothesis Testing

Inference About Comparing Two Populations, Part 1

Inference About Comparing Two Populations, Part 2

Analysis of Variance

Chi-Squared Tests

Simple Linear Regression and Correlation

Multiple Regression

Review of Statistical Inference

Filters

The degrees of freedom for the test statistic for $\mu$ when $\sigma$ is unknown is:

If a sample has 15 observations and a 95% confidence estimate for $\mu$ is needed, the appropriate value of t is 1.753.

When the population standard deviation is unknown and the population is normal, the test statistic for testing hypotheses about $\mu$ is the -distribution with degrees of freedom.

In order to determine the p-value associated with hypothesis testing about the population mean $\mu$ , it is necessary to know the value of the test statistic.

The t-statistic has two variables: the sample and the sample .

The statistic (n - 1)s² / $\sigma$ ² has a chi-squared distribution with n - 1 degrees of freedom if:

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 is normally distributed with variance equal to $\sigma$ ².