Chapter 10: Related-Sample t Tests

A researcher records the amount of time (in minutes) that parent-child pairs spent on social networking sites to test whether they show any generational differences. From the following findings reported in APA format, interpret these results. Parents spent significantly less time on social networking sites compared to their children (MD = 42 minutes), t(29) = 3.275, p < 0.05, d = 0.46. (b) State the sample size.

60 participants

What are the assumptions for a related samples t-test? (Select all that apply.)

> normality > independence within groups

Would each of the following increase, decrease, or have no effect on the value of the test statistic for a related samples t-test? (c) The estimated standard error for difference scores is doubled.

This change will decrease the value of the test statistic.

Would each of the following increase, decrease, or have no effect on the value of the test statistic for a related samples t-test? (b) The sample size is increased.

This change will increase the value of the test statistic.

The estimated standard error for difference scores is in the denominator of the test statistic for the related samples t test.

True

Which of the following is a type of related samples design in which different participants are actually observed in each group, but treated statistically as if they are the same persons in each group?

matched samples design

A researcher records the level of attention among 18 students during an interactive and lecture portion of a single class. If she computes a related samples t test at a 0.05 level of significance (two-tailed test), then what is the critical value for this test?

±2.110

Which of the following is an advantage for selecting related samples compared to selecting independent samples in behavioral research?

> Selecting related samples can be more practical. > Selecting related samples minimizes standard error. > Selecting related samples increases power. > All of the above.

A researcher records the amount of time (in minutes) that parent-child pairs spent on social networking sites to test whether they show any generational differences. From the following findings reported in APA format, interpret these results. Parents spent significantly less time on social networking sites compared to their children (MD = 42 minutes), t(29) = 3.275, p < 0.05, d = 0.46. (c) State the decision to retain or reject the null hypothesis.

Reject the null hypothesis.

Would each of the following increase, decrease, or have no effect on the value of the test statistic for a related samples t-test? (d) The mean difference is decreased.

This change will decrease the value of the test statistic.

Would each of the following increase, decrease, or have no effect on the value of the test statistic for a related samples t-test? (a) The level of significance is reduced from 0.05 to 0.01.

This change will have no effect on the value of the test statistic.

Each of the following is an advantage for using the related-samples design, except

it increases the variability measured in a study. Advantages: > it can be more practical. > it minimizes standard error. > it increases the power of a research design.

A researcher records the amount of time (in minutes) that parent-child pairs spent on social networking sites to test whether they show any generational differences. From the following findings reported in APA format, interpret these results. Parents spent significantly less time on social networking sites compared to their children (MD = 42 minutes), t(29) = 3.275, p < 0.05, d = 0.46. (a) State the research design used (repeated measures or matched pairs).

matched pairs design

Which type of research design can only be used with 2 groups?

matched-pairs

A researcher records the amount of time (in minutes) that parent-child pairs spent on social networking sites to test whether they show any generational differences. From the following findings reported in APA format, interpret these results. Parents spent significantly less time on social networking sites compared to their children (MD = 42 minutes), t(29) = 3.275, p < 0.05, d = 0.46. (d) State the effect size.

medium

For each example, state whether the one-independent, the two-independent, or the related samples t-test is most appropriate. If it is a related samples t-test, indicate whether the test is a repeated measures design or a matched-pairs design. (b) A graduate student selects a sample of 25 participants to test whether the average time students attend to some task is greater than 30 minutes.

one-independent sample t-test

The denominator of the test statistic for a related-samples t test

provides an estimate of the error associated with the difference scores.

For each example, state whether the one-independent, the two-independent, or the related samples t-test is most appropriate. If it is a related samples t-test, indicate whether the test is a repeated measures design or a matched-pairs design. (c) A researcher matches right-handed and left-handed siblings to test whether right-handed siblings express greater emotional intelligence than left-handed siblings.

related samples t-test using the matched-pairs design

For each example, state whether the one-independent, the two-independent, or the related samples t-test is most appropriate. If it is a related samples t-test, indicate whether the test is a repeated measures design or a matched-pairs design. (d) A principal at a local school wants to know how much students gain from being in an honors class. He gives students in an honors English class a test prior to the school year and again at the end of the school year to measure how much students learned during the year.

related samples t-test using the repeated measures design

For each example, state whether the one-independent, the two-independent, or the related samples t-test is most appropriate. If it is a related samples t-test, indicate whether the test is a repeated measures design or a matched-pairs design. (a) A professor tests whether students sitting in the front row score higher than students sitting in the back row.

two-independent sample t-test

A researcher selects a sample of 24 college students and has them rate their liking for two advertisements aimed at improving the image of the college. The researcher finds that liking ratings significantly differed, t = 2.900. Use omega-squared to compute the proportion of variance for this result.

ω2 = 0.24