更新1:
To : 自由自在 Please explain why E = q(0) + pq(1) + p^2q(2) + ....... and not E = p(0) + pq(1) + pq^2(2) + ....
Probability
2011-02-19 5:27 am
Teacher asked Tom and Joe the question : if the probability that a certain car has to be checked in a given week is 0.0175, what is the expected number of consecutive weeks that the car does not require checking? Answer correct to the nearest weeks. Tom said 57 weeks, Joe said 58 weeks. Who is correct? Or both are wrong? Please explain your answer.
回答 (2)
2011-02-19 5:48 am
✔ 最佳答案
http://img823.imageshack.us/img823/4417/48922015.png圖片參考：http://img823.imageshack.us/img823/4417/48922015.png
2011-02-19 11:01:42 補充：
我看這完全是另一個問題,和本題是不一樣的.
2011-02-19 17:46:29 補充：
q is the probability that a check is needed
So Pr that a check is needed in first week = q (i.e. number of week not require a check = 0)
Pr that a check is not needed in first week but 2nd week =pq (1 week does not need a check)
2011-02-19 17:46:34 補充：
Pr that check is not needed in first 2 weeks but third week=p^2q (2 weeks do not need a check), etc
2011-02-20 1:09 pm
這題並不是這樣簡單的，請看http://tw.knowledge.yahoo.com/question/question?qid=1510071403040你就會明白了。
2011-02-20 05:09:45 補充：
圖片參考：http://i212.photobucket.com/albums/cc82/doraemonpaul/yahoo_knowledge/expectedvalue/crazyexpectedvalue9.jpg
參考資料：
concept similar to http://tw.knowledge.yahoo.com/question/question?qid=1010112101356 + http://tw.knowledge.yahoo.com/question/question?qid=1510071403040 + my wisdom of maths
2011-02-20 05:09:45 補充：
圖片參考：http://i212.photobucket.com/albums/cc82/doraemonpaul/yahoo_knowledge/expectedvalue/crazyexpectedvalue9.jpg
參考資料：
concept similar to http://tw.knowledge.yahoo.com/question/question?qid=1010112101356 + http://tw.knowledge.yahoo.com/question/question?qid=1510071403040 + my wisdom of maths
收錄日期: 2021-04-23 23:25:56
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20110218000051KK01156