Exam 9: Testing Means: One-Sample and Two-Independent Sample T Tests

Two researchers (A and B)compute a two-independent sample t test.For both tests,the standard error is the same,but the mean difference between the groups is larger for Researcher A.Which test is more likely to result in a decision to reject the null hypothesis?

Which of the following summarizes a t test that was significant and associated with a large effect size?

Two researchers (A andB)compute a one-sample t test.For both tests,the mean difference between the sample and value stated in the null hypothesis is 5,but the standard error is smaller for Researcher A.Which test is more likely to result in a decision to reject the null hypothesis?

A researcher measures mean health scores of children at a local school and compares these scores to the mean health score known in the general population.Assuming that the population variance is unknown,what type of t test is appropriate for this study?

A researcher has participants rate the likability of a sexually promiscuous person described in a vignette as being male (n = 20)or female (n = 12).The mean likability ratings in each group were 4.0.If the null hypothesis is that there is no difference in likability ratings,then do likability ratings differ at a .05 level of significance?

A local elementary school determined that the average number of volunteers for their "Step into Spring" annual fundraiser has been 14 persons on average (per event).After taking additional measures to recruit volunteers this year,they got 28 people to volunteer.Test whether these additional measures increased the number of volunteers at a .05 level of significance.

The ________ is an inferential statistic used to determine the number of standard deviations in a t distribution that a sample mean deviates from the mean value or mean difference stated in the null hypothesis.

If d = 0.28,then we conclude that mean scores in some population have shifted 0.28 standard deviations below the mean.

A researcher conducts a study and concludes that a new behavioral health treatment program significantly reduces one's risk for disease compared with risk levels in the general population (d = -0.64).Interpret the size of this effect.

The p value is reported with the test statistic of a one-sample and a two-independent sample t test using APA format.

It is most appropriate to report effect size with a significant result.Why is it generally inappropriate to report effect size with insignificant results?

A t test is associated with n - 1 degrees of freedom.

A researcher finds that the mean difference in productivity between employees working the morning shift (n = 16)and the night shift (n = 10)is 5.0 units,and the estimated standard error for the difference is 2.7 units.If the null hypothesis states that there is no difference in productivity,then is this result significant at a .05 level of significance?

The critical values are reported with the test statistic of a one-sample and a two-independent sample t test using APA format.

A researcher reports the following result for a lower-tail critical test at a .05 level of significance,t(40)= 3.212,and accurately concludes that this result is significant.

The estimated standard error in the t statistic uses the ________ to estimate the ________ when the population variance is unknown.

As a requirement for the t test,researchers compute any type of t test with samples selected from populations in which

A researcher conducts two t tests.Test 1 is a one-tailed test with a smaller sample size at a .05 level of significance.Test 2 is a one-tailed test with a larger sample size at a .05 level of significance.What do you know about the critical values for each test?

A researcher reports that stress levels among nurses are higher compared to stress levels in the general population,t(20)= 2.086,p = .05 (d = .12).Was this a one-tailed or a two-tailed test?

Computing a two-independent sample t test is appropriate when