作者goshagainfuc (...)
看板Statistics
标题[问题] 机率一问
时间Mon Oct 23 01:12:37 2006
l. let X be a random variable of the discrete type with pmf p(x) that is
positive on the nennegative integers and is equal to zero elsewhere.
show that
∞
E(X)= Σ [1-F(x)]
x=0
where F(x) is the cdf of X
(帮忙一下吧前面一题是连续的我有算出来但这题离散的就凑不出答案了@@")
2. let X be a random variable with a pdf f(x) and mgf M(t). Suppose f is
symmetric about 0, ( f(-x)=f(x) ). show that
M(-t)=M(t)
(也是凑不出答案@@")
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