Exam 10: One-Sample Tests of Hypothesis

If two samples are used in a hypothesis test for which the combined degrees of freedom is 24, Which one of the following CANNOT be true about the two sample sizes?

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. There are how many degrees of freedom?

A company is researching the effectiveness of a new website design to decrease the time to access A website. Five website users were randomly selected, and their times (in seconds) to access the Website with the old and new designs were recorded. To compare the times, they computed (new Website design time - old website design time). The results follow: If the calculated test statistic is -2.256, what is the decision regarding the hypothesis that the Training was effective in improving customer relationships when tested at a 0.01 significance level?

Of 150 adults who tried a new peach-flavoured peppermint patty, 75 rated it excellent. Of 200 Children sampled, 123 rated it excellent. Using the 0.10 level of significance, can we conclude that There is a significant difference in the proportion of adults and the proportion of children who rate The new flavour as excellent? State the decision rule, the value of the test statistic, and your Decision.

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

The results of a mathematics placement exam at Mercy College for two campuses are as follows: What is the computed value of the test statistic?

A poll of 400 people from village 1 showed 250 preferred chocolate raspberry coffee to the regular Blend while 170 out of 350 in village 2 preferred the same flavor. You wish to test the hypothesis That there is no difference in preferences in the two villages. If you were to use Excel's MegaStat to Assist in your solution to this problem, which test would you use?

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:

Married women are more often than not working outside the home on at least a part-time basis, as Do most mannered men. Does a husband's employment status affect his wife's well being? In an Attempt to answer this question, 20 married female professionals were surveyed as to their job Satisfaction. In this sample, 15 husbands were employed, and 5 were unemployed. The Learning Objective of the study was to compare the mean job satisfaction levels of the married women with Working husbands, with the mean job satisfaction levels of the married women with husbands that Stayed at home. If the p-value obtained from the computer printout is 0.025, does this give sufficient evidence to Conclude that the mean level of job satisfaction for women with working husbands is more than that Of those whose husbands don't work?

i. If the null hypothesis states that there is no difference between the mean income of males and the Mean income of females, then the test is one-tailed. ii. If we are testing for the difference between two population means, it is assumed that the sample Observations from one population are independent of the sample observations from the other Population. iii. If we are testing for the difference between two population means, it is assumed that the two Populations are approximately normal and have equal variances.

The employees at the East Vancouver office of a multinational company are demanding higher Salaries than those offered at the company office located in Oshawa Ontario. Their justification for The pay difference is that the difference between the average price of single-family houses in East Vancouver and that in Oshawa is more than $60,000. Before making a decision, the company Management wants to study the difference in the prices of single-family houses for sale at the two Locations. The results of their search of recent house sales are as follows (in $1000, rounded to the nearest Thousand): Assuming that the population distributions are approximately normal, can we conclude at the 0.05 Significance level that the difference between the two population means is greater than $60,000? If you use the 5% level of significance, what is the critical t value?