When the variances are unknown, a test comparing two independent sample means would use the Student's t distribution

When using independent samples to test the difference between two population means, a pooled variance is used if the population variances are unknown and assumed equal.

When using independent samples to test the difference between two population means, it is desirable but not necessary for the sample sizes to be the same

The test statistic in an F test for equal variances is the ratio of the sample variances.

When testing the difference between two population proportions, it is necessary to use the same size sample from each population.

When the variances are known, a test comparing two independent sample means would use the standard normal distribution.

The difference between two sample proportions p1 - p2 may be assumed normally distributed if each sample has at least 10 "successes" and 10 "failures."

A paired t-test with two columns of 8 observations in each column would use d.f. = 7.

A paired t-test with two columns of 10 observations in each column would use d.f. = 18.

The F test is used to test for the equality of two population variances.

A pooled proportion is calculated by giving each sample proportion an equal weight.

If we reject the null hypothesis using the p-value method then

Which of the following is an example of a two-sample hypothesis test?

For a two-sample hypothesis test of variances, we would use the:

Which of the following is not a characteristic of the F distribution?

We pool the sample variances when

In practice, which of the following tests is more realistic?

Using the p-value method, we reject the null hypothesis if p-value is less than alpha

Select one:

"Currently, only 20 percent of arrested drug pushers are convicted," cried candidate Courageous Calvin in a campaign speech. "Elect me and you'll see a big increase in convictions." A year after his election a random sample of 144 case files of arrested drug pushers showed 36 convictions. For a right-tailed test, the p-value is approximately:

A psychology researcher has a theory that predicts women will tend to carry more cash than men. A random sample of Ersatz University students revealed that 16 females had a mean of $22.30 in their wallets with a standard deviation of $3.20, while 16 males had a mean of $17.30 with a standard deviation of $9.60. The researcher's hypothesis would lead us to perform a"

A random sample of Ersatz University students revealed that 16 females had a mean of $22.30 in their wallets with a standard deviation of $3.20, while 6 males had a mean of $17.30 with a standard deviation of $9.60. The value of the test statistic for a test of equal variances (F calc) is

A psychological researcher has a theory that predicts women will tend to carry more cash than men. A random sample of Ersatz University students revealed that 16 females had a mean of $22.30 in their wallets with a standard deviation of $3.20, while 16 males had a mean of $17.30 with a standard deviation of $9.60.The test statistic for the researcher's hypothesis is

The population means:

Does the Speedo Fastskin II Male Hi-Neck Bodyskin competition racing swimsuit improve a swimmer's 200-yard individual medley performance times? A test of 100 randomly chosen male varsity swimmers at several different universities showed that 66 enjoyed improved times, compared with only 54 of 100 female varsity swimmers. To test for equality in the proportions of men versus women who experienced improvement, the test statistic is approximately:

Group 1 has a mean of 13.4 and group 2 has a mean of 15.2. Both populations are known to have a variance of 9.0 and each sample consists of 18 items. What is the test statistic to test for equality of population means?

Which is not a type of comparison for which you would anticipate a two-sample test?

Assuming unequal variances in a t-test for a zero difference of two means, we would:

At Huge University, a sample of 200 business school seniors showed that 26 planned to pursue an MBA degree, compared with 120 of 800 arts and sciences seniors. We want to know if the proportion is higher in the arts and sciences group. For this test, the assumption of normality is

At Huge University, a sample of 200 business school seniors showed that 26 planned to pursue an MBA degree, compared with 120 of 800 arts and sciences seniors. We want to know if the proportion is higher in the arts and sciences group. The p-value for a left-tailed test is approximately:

Two well-known aviation training schools are being compared using random samples of their graduates. It is found that 70 of 140 graduates of Fly-More Academy passed their FAA exams on the first try, compared with 104 of 260 graduates of Blue Yonder Institute. To compare the two proportions, the assumption of normality of the test statistic is:

Two well-known aviation training schools are being compared using random samples of their graduates. It is found that 70 of 140 graduates of Fly-More Academy passed their FAA exams on the first try, compared with 104 of 260 graduates of Blue Yonder Institute. In a right-tailed test, the conclusion at a = .05 is that we should

Two well-known aviation training schools are being compared using random samples of their graduates. It is found that 70 of 140 graduates of Fly-More Academy passed their FAA exams on the first try, compared with 104 of 260 graduates of Blue Yonder Institute. To compare the pass rates, the pooled proportion would be:

Which of the following is not a characteristic of the F distribution?

Carver Memorial Hospital's surgeons have a new procedure that they think will decrease the variance in the time it takes to perform an appendectomy. A sample of 8 appendectomies using the old method had a variance of 36 minutes, while a sample of 10 appendectomies using the experimental method had a variance of 16 minutes. At α = . 10 in a two-tailed test for equal variances, the critical values are:

Carver Memorial Hospital's surgeons have a new procedure that they think will decrease the variance in the time it takes to perform an appendectomy. A sample of 8 appendectomies using the old method had a variance of 36 minutes, while a sample of 10 appendectomies using the experimental method had a variance of 16 minutes. The value of the test statistic for a test of equal variances (F calc) is

Carver Memorial Hospital's surgeons have a new procedure that they think will decrease the time to perform an appendectomy. A sample of 8 appendectomies using the old method had a mean of 38 minutes with a variance of 36 minutes, while a sample of 10 appendectomies using the experimental method had a mean of 29 minutes with a variance of 16 minutes. For a right-tail test for equal means (assume equal variances), the critical value at α = .10 is:

Carver Memorial Hospital's surgeons have a new procedure that they think will decrease the time to perform an appendectomy. A sample of 8 appendectomies using the old method had a mean of 38 minutes with a variance of 36 minutes, while a sample of 10 appendectomies using the experimental method had a mean of 29 minutes with a variance of 16 minutes. For a right-tail test of means (assume equal variances) the pooled variance is

Carver Memorial Hospital's surgeons have a new procedure that they think will decrease the time to perform an appendectomy. A sample of 8 appendectomies using the old method had a mean of 38 minutes with a variance of 36 minutes, while a sample of 10 appendectomies using the experimental method had a mean of 29 minutes with a variance of 16 minutes. At a = .10, what conclusion can be made in a two-tailed test for equal population variances?

The variable used to predict another variable is called the:

In a test of a new surgical procedure, the five most respected surgeons in FlatBroke Township were invited to Carver Hospital. Each surgeon was assigned two patients of the same age, gender, and overall health. One patient was operated upon in the old way, and the other in the new way. Both procedures are considered equally safe. The time (in minutes) to complete each procedure was carefully recorded. In a right-tail test for a difference of means at α = .05, the test type and critical value are

Select one:

A new policy of "flex hours" is proposed. Random sampling showed that 28 of 50 female workers favored the change, while 22 of 50 male workers favored the change. Management wonders if there is a difference between the two groups. For a test comparing the two proportions, the assumption of normality is

A new policy of "flex hours" is proposed. Random sampling showed that 28 of 50 female workers favored the change, while 22 of 50 male workers favored the change. Management wonders if there is a difference between the two groups. What is the p-value for a two-tailed test?

A new policy of "flex hours" is proposed. Random sampling showed that 28 of 50 female workers favored the change, while 22 of 50 male workers favored the change. Management wonders if there is a difference between the two groups. What is the test statistic to compare the two proportions?

Of 200 youthful gamers (under 18) who tried the new Z-Box-Plus game, 160 rated it "excellent," compared with only 144 of 200 adult gamers (18 or over). The 95 percent confidence interval for the difference of proportions would be approximately:

Of 200 youthful gamers (under 18) who tried the new Z-Box-Plus game, 160 rated it "excellent", compared with only 144 of 200 adult gamers (18 or over). The p-value for a right-tailed test to compare the two proportions would be approximately

Of 200 youthful gamers (under 18) who tried the new Z-Box-Plus game, 160 rated it "excellent", compared with only 144 of 200 adult gamers (18 or over). The pooled proportion for a test to compare the two proportions would be

In a test comparing two proportions, the sample proportions were p1= 12/50 and p2= 18/50. The pooled proportion is

During a test period, an experimental group of 10 vehicles using an 85% ethanol-gasoline mixture showed mean CO2 emissions of 240 pounds per 100 miles, with a standard deviation of 20 pounds. A control group of 14 vehicles using regular gasoline showed mean CO2 emissions of 252 pounds per 100 miles with a standard deviation of 15 pounds. At a = 0.05, in a left-tailed test, the critical value to compare the means (assuming equal variances) is

During a test period, an experimental group of 10 vehicles using an 85% ethanol-gasoline mixture showed mean CO2 emissions of 240 pounds per 100 miles, with a standard deviation of 20 pounds. A control group of 14 vehicles using regular gasoline showed mean CO2 emissions of 252 pounds per 100 miles with a standard deviation of 15 pounds. To test for equal variances in a two-tailed test at a= .10, the critical values are

During a test period, an experimental group of 10 vehicles using an 85% ethanol-gasoline mixture showed mean CO2 emissions of 240 pounds per 100 miles, with a standard deviation of 20 pounds. A control group of 14 vehicles using regular gasoline showed mean CO2 emissions of 252 pounds per 100 miles with a standard deviation of 15 pounds. The value of the test statistic for a test of equal variances is

Jason wants to perform a two-tailed test for equality between two independent sample proportions. Each sample has at least ten "successes" and 10 "failures." Jason's test statistic is -1.44. What is his p-value?

In a random sample of patient records in Cutter Memorial Hospital, six-month postoperative exams were given in 90 out of 200 prostatectomy patients, while in Paymor Hospital such exams were given in 110 out of 200 cases. In comparing these two proportions, normality may be assumed because