推 sasoman: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
推 youngsam:樓上正解 01/05 14:12
※ 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！
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