Re: Looking for feedback for an online multivariate regression tool...

RF...

Two links were mentioned in the OP. The first one mentioned is the one
you want. OMU


Reef Fish wrote:
Old Mac User wrote:
Owen...

I looked at one example from your link. Here are three comments.

I couldn't find any example from the link in his post. On the other
link
it had "multiple regression" which is NOT "multivariate regression", so
that's like Richard Ulrich calling Y = bX a nonlinear regression model.
:-)


First, you seem to have included in the model all possible "variables"
including interactions and quadratics regardless of whether those
factors are "signficant" or not.

This is actually CORRECT, before any analysis of a quadratic
SURFACE associated with a set of candidate variables. The
unimportant main effect or interactions will be dropped ONLY in
the light of the regression results!

For example if you want to fit a quadratic curve in X, you MUST
incluce X, X^2 and a constant. Once the data is there, it may turn
out that the X term is not necessary of the curve is symmetric
around the origin.

Can't comment on the rest -- they may or may not be appropriate if
the user is supposed to EXPLORE the surface to be fitted, rather
than confirm a particular form. In that case, graphics are much
more telling then certain "test statistics".

-- Reef Fish Bob,

Second, there seems to be no guidance mechanism in this software...
no aid to variable selection other than a graphic. For instance, no
t-ratios with each model coefficient, etc.

Third, the "variables" are surely correlated among themselves.
This means that properly attributing effects of the variables is not
likely to be possible.

Some kind of variable selection method would be more appropriate here.

If you wish, send me one example of such data... on one page of
a spread***... with the "variables" clearly identified... and I'll
send
back to you an example of what I mean. Send as an attachment,
by e-mail. OMU





Owen wrote:
Hi, I'm looking for feedback on how to make the following online tool
more user-friendly, intuitive, understandable, and easy to use. Not a
simple task, given that it allows you to play around with multivariate
regression equations... you can get to the tool by going to
http://www.braintechllc.com/mymodels.aspx and then selecting whichever
pre-build model you like. Or you can build your own... I'm hoping for
some honest, genuine, constructive feedback about the usability and
navigatability of the site, and especially about the online tools.

Owen, Member BrainTech, LLC
http://www.braintechllc.com/owen.aspx

.