1. PowerPoint Presentation Materials Statistics: A First Course Donald H. Sanders Robert K. Smidt Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 9-1

2. The general shape of F distributions. Figure 9.1 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 9-2

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4. The critical F value of 4.53 defines the rejection region of the F distribution with 7 degrees of freedom in the numerator and 8 degrees of freedom in the denominator, at  =.05. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 9-4 Figure 9.2

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6. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 9-6 Four procedures followed to conduct hypothesis tests about the means of two normally distributed populations. The correct procedure to use in a given situation depends on the answers to the questions posed in the four diamond-shaped decision symbols. Figure 9.4

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8. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 9-8 Four procedures followed to conduct hypothesis tests about the means of two normally distributed populations. The correct procedure to use in a given situation depends on the answers to the questions posed in the four diamond-shaped decision symbols. Figure 9.4

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10. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Conceptual schematic of the sampling distribution of the differences between sample means. Figure 9.7 9-10

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12. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 9-12 The sampling differences between means when  1 and  2 are known or when n 1 and n 2 are both > 30. Figure 9.8

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