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The random variable X is defined by taking the square of the score obtained by rolling an unbiased dice once. 計算出 x= 1 4 9 16 25 36 p(X=x) 1/6 1/6 1/6 1/6 1/6 1/6 F(x) 1/6 2/6 3/6 4/6 5/6 6/6 E(X)= 15.17 Var(X)用 1x(1-15.17)^2 +.....+ 1x(36-15.17)^2 /6 =149.13 答案跟解答379.14不符合 請問是哪邊出錯了呢? 謝謝~ -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 147.143.227.78