[理工] [古典機率]
Toss a fair dice four times and note the outcomes (X1,X2,X3,X4)
(a) calculate P(X1 < min( X2, X3, X4))
(b) what is the prob that X1 ≦ X2≦ X3 ≦ X4
還想請問第一題的題意 我不懂min放在那邊是什麼意思
(對古典機率超沒感覺 完全不知道怎麼下手)
----------------------------分隔線------------------------------
(a) P(X1 < min( X2, X3, X4)) = n(A)/n(S)
n(S) = 6^4
n(A) = 5^3 + 4^3 + 3^3 + 2^3 + 1^3 ←1.不懂他做什麼運算!!
(b) P(X1 ≦ X2≦ X3 ≦ X4) = n(A)/n(S)
n(S) = 6^4
n(A) = (21+15+10+6+3+1)+ ←2.不懂他做什麼運算!!
(15+10+6+3+1)+
(10+6+3+1)+
(6+3+1)+
(3+1)+1 = 126
--
※ 發信站: 批踢踢實業坊(ptt.cc)
◆ From: 220.142.163.84
→
07/02 12:49, , 1F
07/02 12:49, 1F
→
07/04 07:50, , 2F
07/04 07:50, 2F
→
07/04 09:11, , 3F
07/04 09:11, 3F
※ 編輯: lai90043 來自: 218.175.209.149 (07/05 18:34)
討論串 (同標題文章)