Math Question1
2012-01-11 4:22 am
回答 (1)
2012-01-11 4:51 am
✔ 最佳答案
(i) E(X) = 3 * 0.1 + 4 * 0.2 + 5 * 0.3 + 6 * 0.3 + 7 * 0.1 = 5.1(ii) E(X^2) = 9 * 0.1 + 16 * 0.2 + 25 * 0.3 + 36 * 0.3 + 49 * 0.1 = 27.3
Var(X) = E(X^2) - [E(X)]^2 = 27.3 - (5.1)^2 = 1.29
(iii) E(3X - 2) = 3E(X) - 2 = 3 * 5.1 - 2 = 13.3
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