Joint p.d.f.
2011-04-25 5:39 pm
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回答 (1)
2011-04-25 10:50 pm
✔ 最佳答案
(i)X = -1, 0, 4, 49
P(X) = 125/216,75/216,15/216,1/216
(ii)
E(X)
= (-125 + 4*15 + 49)/216
= -2/27
E(X^2)
= (125 + 16*15 + 49^2)/216
= 461/36
Var(X) = E(X^2) - [E(X)]^2 = 12.8
(iii) Y = -24, 0, 16, 2401
P(Y) = 125/216, 75/216, 15/216, 1/216
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原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20110425000051KK00297