Exam 13: Inference About Comparing Two Populations

The ratio of two independent chi-squared variables divided by their degrees of freedom is:

Additives A food processor wants to compare two additives for their effects on retarding spoilage.Suppose 16 cuts of fresh meat are treated with additive A and 16 are treated with additive 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 -{Additives Narrative} Determine the rejection region at $\alpha$ = .05 and write the proper conclusion.

When the necessary conditions are met,a two-tail test is being conducted at $\alpha$ = .05 to test .The two sample variances are and ,and the sample sizes are n₁ = 25 and n₂ = 25.The calculated value of the test statistic will be F = 2.

The pooled proportion estimate is used when the null hypothesis states that the two population proportions differ by ____________________.

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} Estimate with 95% confidence the ratio of the two population variances and interpret.

When the data from two populations are ____________________ the parameter to be tested and estimated is the difference between the two population proportions.

The number of degrees of freedom associated with the t-test,when the data are gathered from a matched pairs experiment with 8 pairs,is 7.

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.

Engine Wear To compare the wearing of two types of automobile engines,1 and 2,an experimenter chose to "pair" the measurements,comparing the wear for the two types of engines on each of 7 automobiles,as shown below. -{Engine Wear Narrative} Estimate with 90% confidence the mean difference and interpret.