Exam 11: Two-Sample Tests of Hypothesis

To compare the effect of weather on sales of soft drinks,a soda manufacturer sampled two regions of the country with the following results.Is there a difference in sales between the 2 regions? What is your decision? ____________________

For a hypothesis comparing two population means,what is the critical value for a one-tailed hypothesis test,using a 5% level of significance level,with both sample sizes equal to 13? Assume the population standard deviations are equal.

When is it appropriate to use the paired difference t-test?

Accounting procedures allow a business to evaluate their inventory at LIFO (Last In First Out)or FIFO (First In First Out).A manufacturer evaluated its finished goods inventory (in $ thousands)for five products both ways.Based on the following results,is LIFO more effective in keeping the value of his inventory lower? What is the value of calculated t?

A study by a bank compared the average savings of customers who were depositors for three years or less,with those who had been depositors for more than three years.The results of a sample are: What is the p-value if the test statistic is 1.51? _____

Of 250 adults who tried a new multi-grain cereal,"Wow!",187 rated it excellent;of 100 children sampled,66 rated it excellent.What is the pooled proportion?

A national manufacturer of ball bearings is experimenting with two different processes for producing precision ball bearings.It is important that the diameters be as close as possible to an industry standard.The output from each process is sampled and the average error from the industry standard is calculated.The results are presented below. The researcher is interested in determining whether there is evidence that the two processes yield different average errors.Assume that the population standard deviations are equal. What is the null hypothesis?

If the decision is to reject the null hypothesis of no difference between two population proportions at the 5% level of significance,what are the alternate hypothesis and rejection region?

A national manufacturer of ball bearings is experimenting with two different processes for producing precision ball bearings.It is important that the diameters be as close as possible to an industry standard.The output from each process is sampled and the average error from the industry standard is calculated.The results are presented below. The researcher is interested in determining whether there is evidence that the two processes yield different average errors.Assume that the population standard deviations are equal. This example is what type of test?

Accounting procedures allow a business to evaluate their inventory at LIFO (Last In First Out)or FIFO (First In First Out).A manufacturer evaluated its finished goods inventory (in $ thousands)for five products both ways.Based on the following results,is LIFO more effective in keeping the value of his inventory lower? What is the decision at the 5% level of significance?

A financial planner wants to compare the yield of income and growth mutual funds.Fifty thousand dollars is invested in each of a sample of 35 income and 40 growth funds.The mean increase for a two-year period for the income funds is $900.For the growth funds the mean increase is $875.Income funds have a population standard deviation of $35;growth funds have a population standard deviation of $45.At the 0.05 significance level,is there a difference in the mean yields of the two funds? What decision is made about the null hypothesis using and $\alpha$ = 0.05? ____________

Accounting procedures allow a business to evaluate their inventory at LIFO (Last In First Out)or FIFO (First In First Out).A manufacturer evaluated its finished goods inventory (in $ thousands)for five products both ways.Based on the following results,is LIFO more effective in keeping the value of his inventory lower? This example is what type of test?

If samples taken from two populations are not independent,then a test of paired differences is applied.

A national manufacturer of ball bearings is experimenting with two different processes for producing precision ball bearings.It is important that the diameters be as close as possible to an industry standard.The output from each process is sampled and the average error from the industry standard is calculated.The results are presented below. The researcher is interested in determining whether there is evidence that the two processes yield different average errors.Assume that the population standard deviations are equal. What is the alternate hypothesis?

If we are testing for the difference between two population means and assume that the two populations have equal and unknown standard deviations,the degrees of freedom are computed as (n₁)(n₂)- 1.

The paired difference test has (n - 1)degrees of freedom.

If the null hypothesis states that there is no difference between the mean net income of retail stores in Chicago and New York City,then the test is two-tailed.

Administering the same test to a group of 15 students and a second group of 15 students to see which group scores higher is an example of

For a hypothesis comparing two population means,what is the critical value for a one-tailed hypothesis test,using a 5% level of significance level,with both sample sizes equal to 13? The standard deviations for the samples are 5 and 7.Assume the population standard deviations are unequal.

A national manufacturer of ball bearings is experimenting with two different processes for producing precision ball bearings.It is important that the diameters be as close as possible to an industry standard.The output from each process is sampled and the average error from the industry standard is calculated.The results are presented below. The researcher is interested in determining whether there is evidence that the two processes yield different average errors.Assume that the population standard deviations are equal. What is the computed value of t?