Re: Chisquare distribution
hello all,
for a chi-square distribution of n degrees of freedom
the mean value
is n. it is clear that it can not be said that if X
is distributed as
chi-square with degrees of freedom n then
approximately half of the
probability mass lies in the region {x: 0<=x<=n}.
however, is it possible to get any close estimate a
as a function of n
i.e. a(n) such that for the region {x:0<=x<=a(n)} the
probability mass
is atmost half?
thanks
An approximation for the median of a chi-square when the degrees of freedom n is large, say n > 30, is
n*[1-2/(9n)]^3.
Jack
.
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