Chapter 22 and 23 - Chapter 22 Comparing Two Proportions...

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Chapter 22 Comparing Two Proportions
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Chapter 22 Comparing Two Proportions Assumptions: 1. Randomization/Independence Condition: Data should be drawn independently and at random 2. 10% Condition: If the data are sampled without replacement, the sample should not exceed 10% of the population 3. Success/Failure Condition: Both groups should be big enough to have at least 10 successes and 10 failures
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Example Researchers contacted more than 25000 Americans aged 24 or above to find if they have graduated from high school: From 12460 males: 84.9% graduated From 12678 females: 88.1% graduated Create a 90% confidence interval for the difference in graduation rate between males and females. Check the assumptions
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Solution P_{1}^-P_{2}^=-0.032 SE = .00322 Z* = 1.645 Conf. Interval: (-.039, -.0249)
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Chapter 22 Comparing Two Proportions
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Example Retirement: The Employee Benefit Research Institute reports that 27% of males anticipate having enough money to live comfortable in retirement, but only 18% of females express that confidence. If these results were based on samples of 250 people of each gender, would you consider this strong evidence that men and women have different outlooks?
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This note was uploaded on 03/27/2012 for the course STT 200 taught by Professor Dikong during the Spring '08 term at Michigan State University.

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Chapter 22 and 23 - Chapter 22 Comparing Two Proportions...

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