设随机变量X的分布律为P(X=k)=A(2/3)k,(k=1,2,3),则A=?这是一道填空题,更正下,是A(2/3)^K
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![设随机变量X的分布律为P(X=k)=A(2/3)k,(k=1,2,3),则A=?这是一道填空题,更正下,是A(2/3)^K](/uploads/image/z/14978463-15-3.jpg?t=%E8%AE%BE%E9%9A%8F%E6%9C%BA%E5%8F%98%E9%87%8FX%E7%9A%84%E5%88%86%E5%B8%83%E5%BE%8B%E4%B8%BAP%28X%3Dk%29%3DA%282%2F3%29k%2C%28k%3D1%2C2%2C3%29%2C%E5%88%99A%3D%3F%E8%BF%99%E6%98%AF%E4%B8%80%E9%81%93%E5%A1%AB%E7%A9%BA%E9%A2%98%2C%E6%9B%B4%E6%AD%A3%E4%B8%8B%EF%BC%8C%E6%98%AFA%282%2F3%29%5EK)
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设随机变量X的分布律为P(X=k)=A(2/3)k,(k=1,2,3),则A=?这是一道填空题,更正下,是A(2/3)^K
设随机变量X的分布律为P(X=k)=A(2/3)k,(k=1,2,3),则A=?这是一道填空题,
更正下,是A(2/3)^K
设随机变量X的分布律为P(X=k)=A(2/3)k,(k=1,2,3),则A=?这是一道填空题,更正下,是A(2/3)^K
因为 P(X=k)=A(2/3)^k,(k=1,2,3)是概率分布函数
所以其所有概率可能性的积分为1,这里的k只能取1,2,3,也就是X只能取1、2、3
也就是说
P(X = 1) + P(X = 2) + P(X = 3) = 1
A(2/3)^1 + A(2/3)^2 + A(2/3)^3 = 1
(2/3 + 4/9 + 8/27) A = 1
((18 + 12 + 8) / 27) A = 1
( 38 / 27) A = 1
A = 27/38