8.3 Estimation Proportion

# The cea bylaws require that more than 23 of the

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Unformatted text preview: l Estimation 0.7 ± .084 0.616 ≤ p ≤ 0.783 Example 2 The Canadian Education Association (CEA) recently proposed that their union merge with the Canadian Federation of Teachers (CFT). The CEA bylaws require that more than 2/3 of the membership must support any such merger. A sample of 200 CEA members showed that 140 supported the merger. Develop a 99% confidence interval for the proportion of the membership supporting the merger. Does it seem likely that merger vote will pass? α=.01; zα/2 = z0.005 =2.58; = 140/200 = 0.7; n = 200 p 99% Confidence interval: p ± zα 2 0.7 ± 2.58 p (1− p ) n 0.7⋅(1− 0.7) 200 Interval Estimation 0.7 ± .084 0.616 ≤ p ≤ 0.783 Or using MS Excel: Lower: =.7– NORM.S.INV(1–.01/2)*SQRT(.7*(1–.7)/200)=0.616533591 Upper: =.7+NORM.S.INV(1–.01/2)*SQRT(.7*(1–.7)/200)=0.783466409 Example 2 The Canadian Education Association (CEA) recently proposed that their union merge with the Canadian Federation of Teachers (CFT). The CEA bylaws require that more than 2/3 of the membership must support any such merger. A sample of 200 CEA members showed that 140 supported the merger. Develop a 99% confidence interval for the proportion of the membership supporting the merger. Does it seem likely that merger vote will pass? α=.01; zα/2 = z0.005 =2.58; = 140/200 = 0.7; n = 200 p 99% Confidence interval: p ± zα 2 0.7 ± 2.58 p (1− p ) n 0.7⋅(1− 0.7) 200 Interval Estimation 0.7 ± .084 0.616 ≤ p ≤ 0.783 Or using MS Excel: Lower: =.7– NORM.S.INV(1–.01/2)*SQRT(.7*(1–.7)/200)=0.616533591 Upper: =.7+NORM.S.INV(...
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## This document was uploaded on 03/05/2014.

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