Exam 9: Testing the Difference Between Two Means, Two Variances, and Two Proportions

A researcher wanted to determine if using an octane booster would increase gasoline mileage.A random sample of seven cars was selected; the cars were driven for two weeks without the booster and two weeks with the booster. -What is the critical value using

What is the null hypothesis? Use . Refer To: 09-18

Find and , if .

Joan moves into her new apartment and wants to purchase a new couch.She wants to determine if there is any difference between the average costs of couches at two different stores.Test the hypothesis that there is no difference at

70% of students at a university live on campus.A random sample found that 35 of 50 male students and 42 of 50 of female students lived on campus.At the .05 level of significance, is there sufficient evidence To conclude that a difference exists between the proportion of male students who live on campus and the Proportion of female students who live on campus?

A researcher wanted to determine if using an octane booster would increase gasoline mileage.A random sample of seven cars was selected; the cars were driven for two weeks without the booster and two weeks with the booster. -Compute the standard deviation of the difference.

A study of cats and dogs found that 25 of 50 cats and 44 of 60 dogs slept more than 10 hours per day.At the .05 level of significance, is there sufficient evidence to conclude that a difference exists between the Proportion of cats and the proportion of dogs that sleep more than 10 hours per day?

For the samples summarized below, test the hypothesis at that the two variances are equal.

When finding the F -test value, the smaller of the variances is placed in the numerator.

The critical value for a left-tailed t-test for dependent samples is __________ when the degrees of freedom = 7 and

Determine the value of s shown in the figure below, if the degrees of freedom were 7 and 9.

What is the test value? Use Refer To: 09-18

The value of F cannot be negative, because variances are always positive or zero.

Samples are independent when they are not related.

Find when = 15, and = 60

Mauricio Tersignico, a local wine merchant, wants to determine if the average price of domestic wine is less than the average price of imported wine.The data obtained is shown in the table below. -What is the critical value? Use (Use the variances unequal formula.)

A running coach wanted to see whether runners ran faster after eating spaghetti the night before a race. Twenty-four random runners were chosen for this study.They ran a 5-kilometre race after having a Normal dinner the night before, and then a week later, re-ran the same race after having a spaghetti dinner The night before.Their results (in seconds) are in the table below.At , what is the test value for This test?

One poll found that 41% of male voters will support a candidate while another found that 49% of female voters will be in support.To test whether this candidate has equal levels of support between male and Female voters, the null hypothesis should be

A recent survey reported that in a sample of 300 students who attend community colleges, 105 work at least 20 hours a week.In a sample of 225 students attending universities, only 20 students were found to Work at least 20 hours per week.What is the test value?

Donaldson Corporation wants to hire a temporary secretary.There are two employment agencies in town, and it is believed that the average hourly wages charged by both agencies are the same.Test this claim at