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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.

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APPENDIX C | Solutions for Odd-Numbered Problems in the Text 671

CHAPTER 10 The t Test for Two Independent Samples

There are several possible solutions to the matchstick

puzzle in Problem 15 but all involve destroying two of the

existing squares. One square is destroyed by removing two

matchsticks from one of the corners and a second square is

destroyed by removing one matchstick. The three removed

matchsticks are then used to build a new square using a line

that already exists in the figure as the fourth side. One solution

is shown in the following figure.

Figure C3

Original pattern with 5 squares (arrows note matchsticks to remove)

New pattern with 4 squares (arrows note new locations for matchsticks)

1. An independent-measures study uses a separate

sample for each of the treatments or populations being

compared.

3. a. The first sample has s 2 = 12 and the second

has s 2 = 6. The pooled variance is 54 6 = 9

(halfway between).

b. The first sample has s 2 = 12 and the second has

s 2 = 3. The pooled variance is 54 9 = 6 (closer to

the variance for the larger sample).

5. a. The pooled variance is 120.

b. The estimated standard error is 4.00.

c. A mean difference of 8 would produce t = 8 4 =

2.00. With df = 28 the critical values are ±2.048.

Fail to reject H 0

.

7. The null hypothesis says that there is no mean difference

between the two populations of students. The

pooled variance is 20, the estimated standard error

is 2, and t = 8 2 = 4.00. With df = 18, the critical

boundaries are ±2.878. Reject the null hypothesis

and conclude that there is a significant difference in

the high school performance of students who watched

Sesame Street as children and those who did not.

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