STATS 7 Lecture Notes - Lecture 7: Confidence Interval, Statistic, Statistical Parameter
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Chapter 10, exercises 4, 12 (use the margin of error already provided), 14, 15, 24, 29acd. Chapter 11, exercises 4, 29, 30, and 37. 0. 47 (+-) 2 * sqrt(0. 47 (1-0. 47))/(1100)) = (0. 015048) 44% to 50: the 95% confidence interval, 0. 4399 to 0. 500096, estimates the proportion of all adults who favor legalization of marijuana. 10. 14) the confidence level expresses only how often the confidence procedure works in the long run. It does not tell us the probability that a specific interval includes the population value. 10. 15) a. interval width increases (higher confidence makes the interval wider: interval width decreases (lower confidence shortens the interval) 10. 24) a. p =134/190= 0. 705: 0. 705 (+-) 2 * sqrt(0. 705(1-0. 705))/190) The population parameter of interest is more strict 0. 6 or 60: 0. 6 (+-) 2 * sqrt(0. 6(1-0. 6))/537) 56% to 64: the 95% confidence interval, 0. 55772 to 0. 64228, estimates the proportion of all adults in the united states who think that penalties for underage drinking should be more strict.
