Exam 13: Inference About Comparing Two Populations

Independent samples are those for which the selection process for one is not related to the selection process for the other.

The number of degrees of freedom associated with the t-test, when the data are gathered from a matched pairs experiment with 10 pairs, is:

When comparing two population variances, we use the ratio rather than the difference .

Undergraduates' Test Scores 35 undergraduate students who completed two years of college were asked to take a basic mathematics test.The mean and standard deviation of their scores were 75.1 and 12.8, respectively.In a random sample of 50 students who only completed high school, the mean and standard deviation of the test scores were 72.1 and 14.6, respectively. -{Undergraduates' Test Scores Narrative} Can we infer at the 10% significance level that a difference exists between the two groups?

All F-tests for the equality of two population variances are one-tailed tests.

Two measurements from the same individuals is an example of data collected from a(n) ____________________ experiment.

The difference in two sample proportions is a(n) ____________________ estimator of the difference in their respective population proportions.

The degrees of freedom for a test of the mean of the paired differences is the number of ____________________ minus ____________________.

The unequal-variances test statistic of has an approximate ____________________ distribution with degrees of freedom.

In testing the difference between the means of two normally distributed populations, the number of degrees of freedom associated with the unequal-variances t-test statistic usually results in a non-integer number.It is recommended that you:

When testing the equality of two population variances the number in the null hypothesis is 0.

The expected value of the difference of two sample means equals the difference of the corresponding population means when:

Aptitude Test Scores Two random samples of 40 students were drawn independently from two populations of students.Assume their aptitude tests are normally distributed (total points = 100).The following statistics regarding their scores in an aptitude test were obtained: . -{Aptitude Test Scores Narrative} Test at the 5% significance level to determine whether we can infer that the two population means differ.

Two measurements from the same individuals is an example of data collected from a matched pairs experiment.

The F-test used for testing the difference in 2 population variances is always a one-tailed test.

We compare two population variances by examining their ____________________.

If there are 10 pairs of data in a matched pairs experiment, the degrees of freedom for the corresponding t-test is 18.

We use a t-test to determine whether two population variances are equal.

The pooled-variances t-test requires that the two population variances need not be the same.

The variance of the difference in sample proportions equals the difference of their population variances.