Exam 13: Inference About Comparing Two Populations

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.

Independent samples are those for which the selection process for one is not related to the selection process for the other.

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

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} Can we infer at the 5% significance level that the proportions of male and female voters who intend to vote for the Democrat candidate differ?

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.

Given the information: ,the number of degrees of freedom that should be used in the pooled variance t-test is:

The test statistic for testing for the equality of two population variances has an F-distribution with ____________________ and ____________________ degrees of freedom.

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

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} Calculate the value of the test statistic for testing the equality of the population variances,and write the proper conclusion.

Speed Limits Violation Do out-of-state motorists violate the speed limit more frequently than in-state motorists? This vital question was addressed by the highway patrol in a large eastern state.A random sample of the speeds of 2,500 randomly selected cars was categorized according to whether the car was registered in the state or in some other state and whether or not the car was violating the speed limit.The data follow. ​ ​ -{Speed Limits Violation Narrative} Briefly describe what the interval estimate tells you.