Re: [問題]統計三個問題

看板Statistics作者 (立志打敗邪惡的ETS軍團)時間16年前 (2008/01/05 02:34), 編輯推噓2(200)
留言2則, 2人參與, 最新討論串2/2 (看更多)
※ 引述《oceanboy0605 ()》之銘言: : 以下我有統計三題我各位幫忙,除了有過程之外, : 最好需要有詳細解說我會比較容易瞭解~謝謝 : 1.求算二項分配的眾數 先查一下什麼叫眾數。 然後再試P(X=x)=P(X=x+1) ,X~Bin(n,p) : 2.If 5% of the tires purchased by a cab company last less than 6 months : and if 20 tires are purchased, calculate the probability that at most : 2 of the tires will expire in six months using. 這一題有很難嗎? X_i~bin(1,P(tires 6個月內 expire)=0.05) Y=X_1+...+X_20~bin(20,P=0.05) : If the mean length of life a tire 2 years. Use the exponential distribution : to calculate the probability that the life of a tire will be less than : 6 months? W~指數分配 mean length of life a tire 2 years 計算 P(W<6)=1-P(W>6) : 3.Suppose the lifelime of an electronic tube has an exponential distribution : with a mean time of 1/λ hours. Find the expected lifelime of a tube,given : that the tube has lasted at least T hours. 前二題都很懂,再來研究這題吧! -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 219.84.254.140

01/05 08:52, , 1F
第一題應該P(X=x)>=P(X=x+1)、P(X=x)>=P(X=x-1)才對吧
01/05 08:52, 1F

01/05 14:12, , 2F
樓上正解
01/05 14:12, 2F
文章代碼(AID): #17VdmpBf (Statistics)
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文章代碼(AID): #17VdmpBf (Statistics)