Re: how to determine the variance of dependant variable when all the var. of ind. variables r known in a linear relation



Greg Heath wrote:

Jerry wrote:


hi, here is the question,

if we know,
y = a * X1 + b * X2 + c

and we also know the variance of X1 and X2, how to evaluate the
variance of the Y?



Plug in and simplify:

VAR(y) = E{ (y - E{y} )^2 }

Hope this helps.



Not much. It is much simpler than that.

--
Stephen J. Herschkorn sjherschko@xxxxxxxxxxxx
Math Tutor on the Internet and in Central New Jersey and Manhattan

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