Question below ;
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我唔明係最後果個問題, "To be absolutely sure of obtaining the desired accuracy how many houseflies should be taken ?",我唔明點解佢個solution 要咁做...(我都唔知點做)... 淨係解呢part ok....
confidence interval
2010-02-17 7:49 pm
回答 (1)
2010-02-18 1:01 am
✔ 最佳答案
因為absolutely sure 表示無論真實的p是多少﹐其估出來的p的標準差都要小於或等於0.03有沒有可能做到?有的。因為p(1-p)是有最大值的﹐您可以用二次方程或微積分等方法知道p=0.5時p(1-p)有最大值0.25
由sqrt[p(1-p)/n]<=0.03
=>n>=p(1-p)/(0.03)^2
=>n>=0.25/(0.03)^2=278 [您看到為甚麼要用p(1-p)的最大值了吧!]
收錄日期: 2021-04-26 14:00:05
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20100217000051KK00378