Exam 10: Hypothesis Testing, Effect Size, and and Confidence Intervals: Two-Sample Designs

The scores that follow were obtained before and after a Tai-Chi workshop. Higher scores indicate a greater calmness. Set $\alpha$ = .01 and test for a significant difference with a t test. Find d. Write a sentence to summarize your conclusion. Participant Before After J. U. 4 7 S. T. 3 5 A. S. 7 9 M. I. 2 4 L. E. 6 7

Data Set 10-5: This experiment is modeled after part of the data needed to demonstrate the Hawthorne Effect. Four assembly-line workers, who normally had two coffee breaks and an hour for lunch, participated in a week-long experiment in which they gave up both coffee breaks and half their lunch hour. Productivity (units produced per hour) for these four was measured under both conditions and is shown below. Productivity/hour Leisurely Schedule Rushed Schedule 6 6 3 5 4 5 5 6 -The proper conclusion for Data Set 10-5 is that the leisurely schedule results in productivity that is

Identify the following as paired samples or independent samples. In each case, give the appropriate df. -The first 10 persons who arrived for a church service filled out a questionnaire on attitudes toward religion. The first 10 who were late for the service were spotted and, after the service, they filled out the same questionnaire.

" depends on the number of observations minus the number of relations among the observations"is a statement about how to calculate

Data Set 10-5: This experiment is modeled after part of the data needed to demonstrate the Hawthorne Effect. Four assembly-line workers, who normally had two coffee breaks and an hour for lunch, participated in a week-long experiment in which they gave up both coffee breaks and half their lunch hour. Productivity (units produced per hour) for these four was measured under both conditions and is shown below. Productivity/hour Leisurely Schedule Rushed Schedule 6 6 3 5 4 5 5 6 -The effect size index for Data Set 10-5 is

Indicate whether each design below is independent samples or paired samples and where possible, give the degrees of freedom. -Two groups of rats differed in sleep deprivation. One group was deprived by being dumped into water every time they began to sleep, the other group was dumped into water every other time they began to sleep. For all rats biogenic amines were measured.

Identify the design of each experiment below as paired samples or independent samples. Give the degrees of freedom in each case. -Thirty-one bulls were compared to 31 bears for signs of depression on October 30, 1929.

In a paired samples design, High Socialist (HS) countries were compared to Low Socialist (LS) countries. On the Quality Index (QI) the HS scored 77 and the LS scored 73. A two-tailed test with a $\alpha$ level of .05 was adopted. A t value of 2.30 was found. Which conclusion follows?

Which of these phrases is not like the others? Which of these phrases doesn't belong with the other three?

Caused, produced, and responsible for are words and phrases that are justified when the experiment

If you have an independent-samples design, you can be sure that

Identify the design of each experiment below as paired samples or independent samples. Give the degrees of freedom in each case. -The proportion of leaves fallen were compared on October 14 for 11 willow oak trees and 11 water oak trees.

Data Set 10-2: The IQs of a group of special education students were compared to the IQs of their siblings who were not in special education. The following data were obtained. Special Ed Not Special Ed 70 104 65 99 67 95 -The standard error of the difference for Data Set 10-2 is

Identify the following as paired samples or independent samples. In each case, give the appropriate df. -Thirteen volunteers weighed themselves before and after a two-day fast.

Which of the following answers has effect size indexes that are considered small?

If you have a paired-samples design, you can be sure that

One year almost all the cowboys at the mythical Stats Bar-X Ranch quit their jobs. Half of them went to law school and were admitted to the bar. The other half skipped law school but even so were admitted to a bar, where a limbo contest took place between the two groups. The numbers below are each participant's best score, showing just how flexible each was. Compare the two groups with the appropriate t test, calculate an effect size index, and write an interpretation. (In a limbo contest, low scores are better than high scores.) Lawyers Others 3.4 in. 3.4. 3.6 in. 3.9 in. 3.4 in. 3.11 in. 3.1 in. 3.8. 3.5 in. 3.8.

With an acknowledgment to Sesame Street, "Which of these things is not like the others, which of these things doesn't belong?"

The book's description of an experiment included the phrase, "treat them exactly alike except for one thing."The italicized phrases are related to a(n)_________ variable and a(n)_________ variable, respectively.

The logic of null hypothesis statistical testing (NHST) is to assume that two populations have