Exam 11: Hypothesis Tests and Estimation for Population Variances

A frozen food company that makes burritos currently has employees making burritos by hand.It is considering purchasing equipment to automate the process and wants to determine if the automated process would result in lower variability of burrito weights.To conduct a hypothesis test using a 0.05 level of significance,the proper format for the null and alternative hypotheses is (where the current by-hand process is process 1 and the automated process is process 2). H₀ : ≤ H_a : >

A consulting report that was recently submitted to a company indicated that a hypothesis test for a single population variance was conducted.The report indicated that the test statistic was 34.79,the hypothesized variance was 345 and the sample variance 600.However,the report did not indicate what the sample size was.What was it?

To test the following hypotheses at the 0.05 level of significance,using a sample size of n = 15. H₀ : σ² = 0.05 H_A : σ² ≠ 0.05 What is the upper tail critical value?

There is interest at the American Savings and Loan as to whether there is a difference between average daily balances in checking accounts that are joint accounts (two or more members per account)versus single accounts (one member per account).To test this,a random sample of checking accounts was selected with the following results: Based upon these data,if tested using a significance level equal to 0.10,the assumption of equal population variances should be rejected.

Two airlines are being compared with respect to the time it takes them to turn a plane around from the time it lands until it takes off again.The study is interested in determining whether there is a difference in the variability between the two airlines.They wish to conduct the hypothesis test using an alpha = 0.02.If random samples of 20 flights are selected from each airline,what is the appropriate F critical value?

If a hypothesis test for a single population variance is to be conducted using a significance level of 0.10,a sample size of n = 16,and the test is a one-tailed upper-tail test,the critical value is:

A two-tailed test for two population variances could have a null hypothesis like the following: H₀ : =

One of the key quality characteristics in many service environments is that the variation in service time be reasonably small.Recently,a major amusement park company initiated a new line system at one of its parks.It then wished to compare this new system with the old system in place at a comparable park in another state.At issue is whether the standard deviation in waiting time is less under the new line system than under the old line system.The following information was collected: Assuming that it wishes to conduct the test using a 0.05 level of significance,the correct null and alternative hypotheses would be: H₀ : ≠ H_a : =

If we are interested in performing a one-tailed,upper-tail hypothesis test about a population variance where the level of significance is .05 and the sample size is n = 20,the critical chi-square value to be used is 30.1435.