Exam 11: Two-Sample Tests of Hypothesis

A recent study focused on the amount of money single men and women save monthly. The information is summarized here. Assume that the population standard deviations are equal. At the 0.01 significance level,do women save more money than men? What is the value of the test statistic for this hypothesis test?

A recent study focused on the number of times men and women send a Twitter message in a day. The information is summarized here. At the 0.01 significance level,we ask if there is a difference in the mean number of times men and women send a Twitter message in a day. What is the p-value for this hypothesis test?

A recent study focused on the amount of money single men and women save monthly. The information is summarized here. Assume that the population standard deviations are equal. At the 0.01 significance level,do women save more money than men? What is the test statistic for this hypothesis?

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.

An investigation of the effectiveness of a training program to improve customer relationships included a pre-training and a post-training customer survey. To compare the differences they computed post-training survey score − pre-training survey score. Seven customers were randomly selected and completed both surveys. The results are shown here. What is the value of the test statistic?

If the null hypothesis that two means are equal is true,where will 97% of the computed z-values lie between?

If we are testing for the difference between two population means and assume that the two populations have equal but unknown standard deviations,the sample standard deviations are pooled to compute the best estimated variance.

The following table shows sample salary information for employees with bachelor's and associate's degrees for a large company in the Southeast United States. The point estimate of the difference between the means of the two populations is ________.

Which condition must be met to conduct a test for the difference in two sample means using a z-statistic?

The net weights (in grams)of a sample of bottles filled by a machine manufactured by Edne,and the net weights of a sample filled by a similar machine manufactured by Orno,Inc.,are shown here. Testing the claim at the 0.05 level that the mean weight of the bottles filled by the Orno machine is greater than the mean weight of the bottles filled by the Edne machine,what is the critical value? Assume equal standard deviations for both samples.

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 measured in millimeters. The results are presented here. The researcher is interested in determining whether there is evidence that the two processes yield different average errors. The population standard deviations are unknown but are assumed equal. What is the null hypothesis?

A recent study focused on the number of times men and women send a Twitter message in a day. The information is summarized here. At the 0.01 significance level,we ask if there is a difference in the mean number of times men and women send a Twitter message in a day. What is the value of the test statistic for this hypothesis test?

A recent study focused on the number of times men and women send a Twitter message in a day. The information is summarized here. At the 0.01 significance level,is there a difference in the mean number of times men and women send a Twitter message in a day? Based on the p-value,what is your conclusion?

Accounting procedures allow a business to evaluate its inventory costs based on two methods: LIFO (last in first out)or FIFO (first in first out). A manufacturer evaluated its finished goods inventory (in $000s)for five products with the LIFO and FIFO methods. To analyze the difference,they computed FIFO − LIFO for each product. Based on the following results,does the LIFO method result in a lower cost of inventory than the FIFO method? This example is what type of test?

Accounting procedures allow a business to evaluate its inventory costs based on two methods: LIFO (last in first out)or FIFO (first in first out). A manufacturer evaluated its finished goods inventory (in $000s)for five products with the LIFO and FIFO methods. To analyze the difference,they computed FIFO − LIFO for each product. We would like to determine if the LIFO method results in a lower cost of inventory than the FIFO method. What is the value of calculated t?

Consider independent simple random samples that are taken to test the difference between the means of two populations. The variances of the populations are unknown but are assumed to be equal. The sample sizes of each population are n₁ = 37 and n₂ = 45. The appropriate distribution to use is the ________.

Accounting procedures allow a business to evaluate their inventory costs based on two methods: LIFO (last in first out)or FIFO (first in first out). A manufacturer evaluated its finished goods inventory (in $000s)for five products with the LIFO and FIFO methods. To analyze the difference,they computed FIFO − LIFO for each product. We would like to determine if the LIFO method results in a lower cost of inventory than the FIFO method. What are the degrees of freedom?

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

Twenty randomly selected statistics students were given 15 multiple choice questions and 15 open-ended questions,all on the same material. The professor was interested in determining if students scored higher on the multiple choice questions. This experiment is an example of ________.

Two samples,one of size 14 and the second of size 13,are selected to test the difference between two population means. How many degrees of freedom are used to find the critical value? Assume the population standard deviations are equal.