[文商] 統計-96-淡江-保險

看板Grad-ProbAsk作者 (勤學統計)時間16年前 (2009/05/31 14:18), 編輯推噓3(3推 0噓 4→)
留言7則, 5人參與, 最新討論串1/1
Suppose there are two boxes. Box I contains 20 articles, of which 5 are defective, and box II contains 30 articles, of which 6 are defective. One article is randomly selected from each box, and the selections from the two boxes are independent. Let X denote the total mumber of defective articles obtained. Determine the probability distribution of X. X→Bin(n=2,p=1/20) 請問　n=2跟p=1/20是怎麼求出來的呢？ 謝謝～ -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 140.113.177.99
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05/31 17:52, , 1F
答案不對吧...>.<"
05/31 17:52, 1F
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05/31 18:35, , 2F
是喔　那麼這題要怎麼算呢
05/31 18:35, 2F
推
05/31 23:42, , 3F
就X=0,1,2的狀況跟機率都寫出來就好
05/31 23:42, 3F
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06/01 00:48, , 4F
但是我有點看不懂題意　不知道過程怎麼解的
06/01 00:48, 4F
推
06/01 02:55, , 5F
P(X=0)=0.75*0.8=0.6 P(X=1)=0.75*0.2+0.25*0.8=0.35
06/01 02:55, 5F
→
06/01 02:57, , 6F
P(X=2)=0.25*0.2=0.05
06/01 02:57, 6F
推
06/01 12:32, , 7F
K大正解
06/01 12:32, 7F
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