21.01.2022 Views

Statistics for the Behavioral Sciences by Frederick J. Gravetter, Larry B. Wallnau ISBN 10: 1305504917 ISBN 13: 9781305504912

Statistics is one of the most practical and essential courses that you will take, and a primary goal of this popular text is to make the task of learning statistics as simple as possible. Straightforward instruction, built-in learning aids, and real-world examples have made STATISTICS FOR THE BEHAVIORAL SCIENCES, 10th Edition the text selected most often by instructors for their students in the behavioral and social sciences. The authors provide a conceptual context that makes it easier to learn formulas and procedures, explaining why procedures were developed and when they should be used. This text will also instill the basic principles of objectivity and logic that are essential for science and valuable in everyday life, making it a useful reference long after you complete the course.

Statistics is one of the most practical and essential courses that you will take, and a primary goal of this popular text is to make the task of learning statistics as simple as possible. Straightforward instruction, built-in learning aids, and real-world examples have made STATISTICS FOR THE BEHAVIORAL SCIENCES, 10th Edition the text selected most often by instructors for their students in the behavioral and social sciences. The authors provide a conceptual context that makes it easier to learn formulas and procedures, explaining why procedures were developed and when they should be used. This text will also instill the basic principles of objectivity and logic that are essential for science and valuable in everyday life, making it a useful reference long after you complete the course.

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

392 CHAPTER 12 | Introduction to Analysis of Variance

3. The populations from which the samples are selected must have equal variances

(homogeneity of variance).

Ordinarily, researchers are not overly concerned with the assumption of normality,

especially when large samples are used, unless there are strong reasons to suspect the

assumption has not been satisfied. The assumption of homogeneity of variance is an important

one. If a researcher suspects it has been violated, it can be tested by Hartley’s F-max

test for homogeneity of variance (Chapter 10, p. 314).

Finally, if you suspect that one of the assumptions for the independent-measures

ANOVA has been violated, you can still proceed by transforming the original scores

to ranks and then using an alternative statistical analysis known as the Kruskal-

Wallis test, which is designed specifically for ordinal data. The Kruskal-Wallis test is

presented in Appendix E. The Kruskal-Wallis test also can be useful if large sample

variance prevents the independent-measures ANOVA from producing a significant

result.

LEARNING CHECK

1. A researcher reports an F-ratio with df = 3, 36 for an independent-measures experiment.

How many treatment conditions were compared in this experiment?

a. 3

b. 4

c. 36

d. 39

2. The following table shows the results of an analysis of variance comparing

three treatment conditions with a sample of n = 7 participants in each treatment.

Note that several values are missing in the table. What is the missing

value for SS total

?

a. 16

b. 23

c. 29

d. 56

Source SS df MS

Between 20 xx xx F = xx

Within xx xx 2

Total xx xx

3. A research report concludes that there are significant differences among treatments,

with “F(2,27) = 8.62, p < .01, η 2 = 0.28.” If the same number of participants was

used in all of the treatment conditions, then how many individuals were in each

treatment?

a. 7

b. 9

c. 10

d. cannot determine without additional information

ANSWERS

1. B, 2. D, 3. C

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!