Answers to selected problems of Chapter 8

Answers to selected problems of Chapter 8 - CHAPTER 8:...

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CHAPTER 8: Answers to the selected problems 8.4 a) The point estimate is the proportion of the sample: 314/1472=0.2133. b) The margin of error of 0.02 is a prediction that the sample proportion falls within 0.02 of the population proportion. It helps us to gauge the accuracy of the sample proportion point estimate. 8.7 a) The margin of error for a 95% confidence interval would be 1.96 times the standard error of 0.01, which is 0.02. It is very likely that the population proportion is no more than 0.02 lower or 0.02 higher than the reported sample proportion. b) The 95% confidence interval includes all points within the margin of error of the mean. Lower endpoint: 0.86 – 0.02 = 0.84; upper endpoint: 0.86 + 0.02 = 0.88. The confidence interval goes from 0.84 to 0.88. This is the interval containing the most believable values for the parameter. 8.12 8.15 a) We can obtain the value reported under “Sample p” by dividing the number of those in favor by the total number of respondents, 1885/2815. b) We can be 95% confident that the proportion of the population who are in favor of

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This note was uploaded on 08/04/2011 for the course MATH 2300 taught by Professor Staff during the Spring '08 term at Texas Tech.

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Answers to selected problems of Chapter 8 - CHAPTER 8:...

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