It is polite to tell us more about yourself than
your first name when asking for advice.
The answer is that the sum of squares of the X's
is a maximum when the points are at the extremes,
and the variance of the coefficient is inversely
proportional to this sum of squares. It is a
worthwhile exercise to prove this for yourself --
it is not difficult.
Jennifer Howser wrote:
>
> My text book states that the tandard error of the regression coefficient B^
> varies inversely with the variance of X, one can improve the significnance
> of the estimated parameter by selecting values of X at the endpoints of the
> range of possible values. However, it does not explain why it is desirable,
> could someone explain to me why.
>
> Thanks,
>
> Jenny
--
Bob Wheeler --- (Reply to: [EMAIL PROTECTED])
ECHIP, Inc.
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