Exam 13: Inference About Comparing Two Populations

Both the equal-variances and unequal variances test statistic and confidence interval estimator of require that the two populations be normally distributed.

(True/False)

4.7/5

(38)

Question 21

In constructing a confidence interval estimate for the difference between two population proportions,we:

(Multiple Choice)

4.8/5

(40)

Question 22

In testing for differences between the means of two independent populations the null hypothesis is:

(Multiple Choice)

4.7/5

(31)

Question 23

Fitness Program A statistician wants to test for the equality of means in two independent samples drawn from normal populations of people enrolled in a fitness program.However,he will not perform the equal-variance t-test of the difference between the population means if the condition necessary for its use is not satisfied.The number of pound lost at the of the program data follow: -{Fitness Program Narrative} Can the statistician conclude at the 5% significance level that the required condition is not satisfied?

(Essay)

4.8/5

(42)

Question 24

The sampling distribution of is normal if the sampled populations are normal,and approximately normal if the populations are nonnormal and the sample sizes n₁ and n₂ are large.

(True/False)

4.9/5

(33)

Question 25

The best estimator of the difference between two population means is the difference between two sample means .

(True/False)

4.8/5

(36)

Question 26

The pooled proportion estimate is used when the null hypothesis states that the two population proportions differ by some non-zero number.

(True/False)

4.9/5

(43)

Question 27

If the sample sizes are large enough so the conditions are met,the difference between two sample proportions has an approximate ____________________ distribution.

(Essay)

4.7/5

(36)

Question 28

In testing the difference between two population means using two independent samples,we use the pooled variance in estimating the standard error of the sampling distribution of the sample mean difference if the populations are normal with equal variances.

(True/False)

4.8/5

(25)

Question 29

If you are testing to see if a weight loss program is working,and you subtract the weights after - before for a group of 10 people,the alternative hypothesis is that the mean difference is ____________________ 0.

(Essay)

4.9/5

(33)

Question 30

Two independent samples of sizes 40 and 50 are randomly selected from two populations to test the difference between the population means .Assume the population variances are known.The sampling distribution of the sample mean difference is:

(Multiple Choice)

4.9/5

(33)

Question 31

If you are testing to see if a weight loss program is working,and you subtract the weights before -fter for a group of 10 people,the alternative hypothesis is that the mean difference is ____________________ 0.

(Essay)

4.8/5

(33)

Question 32

Antioxidants A food processor wants to compare two antioxidants for their effects on retarding spoilage.Suppose 16 cuts of fresh meat are treated with antioxidant A and 16 are treated with antioxidant B,and the number of hours until spoilage begins is recorded for each of the 32 cuts of meat.The results are summarized in the table below -{Antioxidants Narrative} Explain how to use the 95% confidence interval for testing the equality of the two population variances at the 5% level.

(Essay)

4.8/5

(27)

Question 33

Which of the following is a required condition for using the normal approximation to the binomial in testing the difference between two population proportions?

(Multiple Choice)

4.7/5

(25)

Question 34

The F-test used for testing the difference in 2 population variances is always a one-tailed test.

(True/False)

4.7/5

(30)

Question 35

When two population variances are ____________________ we estimate each population variance with its sample variance.The test statistic of is approximately Student t-distributed with n₁ + n₂ - 2 degrees of freedom.

(Essay)

4.7/5

(36)

Question 36

When the population variances are unequal,we estimate each population variance with its sample variance.Hence,the unequal-variances test statistic of is approximately Student t-distributed with n₁ + n₂ - 2 degrees of freedom.

(True/False)

4.9/5

(37)

Question 37

Senatorial Election A political poll immediately prior to a senatorial election reveals that 145 out of 250 male voters and 105 out of 200 female voters intend to vote for the Democrat candidate. -{Senatorial Election Narrative} What is the p-value of the test?

(Essay)

4.9/5

(33)

Question 38

Suppose we randomly selected 250 people,and on the basis of their responses to a survey we assigned them to one of two groups: high-risk group and low-risk group.We then recorded the blood pressure for the members of each group.Such data are called:

(Multiple Choice)

4.9/5

(43)

Question 39

Antioxidants A food processor wants to compare two antioxidants for their effects on retarding spoilage.Suppose 16 cuts of fresh meat are treated with antioxidant A and 16 are treated with antioxidant B,and the number of hours until spoilage begins is recorded for each of the 32 cuts of meat.The results are summarized in the table below -{Antioxidants Narrative} Develop the 95% confidence interval estimate of the ratio of the two population variances.

(Essay)

4.8/5

(32)

Question 40

Showing 21 - 40 of 169

Exam 13: Inference About Comparing Two Populations

Both the equal-variances and unequal variances test statistic and confidence interval estimator of require that the two populations be normally distributed.

In constructing a confidence interval estimate for the difference between two population proportions,we:

In testing for differences between the means of two independent populations the null hypothesis is:

The sampling distribution of is normal if the sampled populations are normal,and approximately normal if the populations are nonnormal and the sample sizes n1 and n2 are large.

The best estimator of the difference between two population means is the difference between two sample means .

The pooled proportion estimate is used when the null hypothesis states that the two population proportions differ by some non-zero number.

If the sample sizes are large enough so the conditions are met,the difference between two sample proportions has an approximate ____________________ distribution.

In testing the difference between two population means using two independent samples,we use the pooled variance in estimating the standard error of the sampling distribution of the sample mean difference if the populations are normal with equal variances.

If you are testing to see if a weight loss program is working,and you subtract the weights after - before for a group of 10 people,the alternative hypothesis is that the mean difference is ____________________ 0.

Two independent samples of sizes 40 and 50 are randomly selected from two populations to test the difference between the population means .Assume the population variances are known.The sampling distribution of the sample mean difference is:

If you are testing to see if a weight loss program is working,and you subtract the weights before -fter for a group of 10 people,the alternative hypothesis is that the mean difference is ____________________ 0.

Which of the following is a required condition for using the normal approximation to the binomial in testing the difference between two population proportions?

The F-test used for testing the difference in 2 population variances is always a one-tailed test.

When two population variances are ____________________ we estimate each population variance with its sample variance.The test statistic of is approximately Student t-distributed with n1 + n2 - 2 degrees of freedom.

When the population variances are unequal,we estimate each population variance with its sample variance.Hence,the unequal-variances test statistic of is approximately Student t-distributed with n1 + n2 - 2 degrees of freedom.

Senatorial Election A political poll immediately prior to a senatorial election reveals that 145 out of 250 male voters and 105 out of 200 female voters intend to vote for the Democrat candidate. -{Senatorial Election Narrative} What is the p-value of the test?

Suppose we randomly selected 250 people,and on the basis of their responses to a survey we assigned them to one of two groups: high-risk group and low-risk group.We then recorded the blood pressure for the members of each group.Such data are called:

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 a Population

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 sampling distribution of is normal if the sampled populations are normal,and approximately normal if the populations are nonnormal and the sample sizes n₁ and n₂ are large.

When two population variances are ____________________ we estimate each population variance with its sample variance.The test statistic of is approximately Student t-distributed with n₁ + n₂ - 2 degrees of freedom.

When the population variances are unequal,we estimate each population variance with its sample variance.Hence,the unequal-variances test statistic of is approximately Student t-distributed with n₁ + n₂ - 2 degrees of freedom.