Thank you very much to all for all your responses.
@Dr. Winsemius, E[f(X)] >=f(E(X)) if f is convex. Now we know |x| is convex
function, so clearly in this scenario if we compute the expectation of the
((X1+X2+X3)/3-X4) and then take the absolute, then, we will get a lower bound
of the expectation I want to find.
On Saturday, August 29, 2015 7:24 PM, David Winsemius
<dwinsem...@comcast.net> wrote:
On Aug 29, 2015, at 11:35 AM, Shant Ch via R-help wrote:
> Hello Dr. Berry,
>
> I know the theoretical side but note we are not talking about expectation of
> sums rather expectation of ABSOLUTE value of the function
> (X1/3+X2/3+X3/3-X4), i.e. E|X1/3+X2/3+X3/3-X4| , I don't think this can be
> handled for log normal distribution by integrals by hand.
>
To Shnant Ch;
I admit to puzzlement (being a humble country doctor). Can you explain why
there should be a difference between the absolute value of an expectation for a
sum of values from a function, in this case dlnorm, that is positive definite
versus an expectation simply of the sum of such values?
--
David Winsemius
Alameda, CA, USA
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