On Mon, 30 Jun 2003 15:15:03 +0800, "ZHANG Yan" <[EMAIL PROTECTED]>
wrote:
> Suppose a positive random varialbe X with pdf f_X(x) and 0<x1<x<x2.
> Given a value A between x1 and x2,i.e. x1<A<x2. Then the range is divided
> into two pars, [x1, A] and [A, x2]. I need to find the average of X in the
> range [x1,A], and additionly the average value of X in the range [A, x2].
> how to write the expression?
Assuming that f is continuous and P(a<=X<=b)>0
b
Integral x*f(x) dx
a
E(X|a<=X<=b) = ------------------
b
Integral f(x) dx
a
Regards
Horst
.
.
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