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Chapter 1 - Intro

Chapter 2 - Methods for Describing Sets of Data

Chapter 3 - Probability

Chapter 4 - Discrete Random Variables

Chapter 5 - Normal Random Variables

Chapter 6 - Sampling Distributions

Chapter 7 - Confidence Intervals

Chapter 8 - Tests of Hypothesis: One Sample

Chapter 9 - Confidence Intervals and Hypothesis Tests: Two Samples Sample Exam I: Chapters 1 & 2

Sample Exam II: Chapters 3 & 4

Sample Exam III: Chapters 5 & 6

Sample Exam IV: Chapters 7 & 8

### Example 136

Example 136:  When investigating the link between birth weights and IQ scores, researchers found that 28 subjects with birth weights less than 1000g had a mean IQ of 95.5 and a standard deviation of 16.0.  For 27 subjects with normal birth weights, the mean IQ was 104.9 with a standard deviation of 14.5.  At the 5% significance level, test the claim that low birth weight children have lower IQs than normal birth weight children (assume IQ scores are normally distributed and the variances are equal).  Is there a possible problem with the assumption of equal variances here?

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