In article <[EMAIL PROTECTED]>,
[EMAIL PROTECTED] wrote:
> On Wed, 23 Feb 2000 19:14:10 GMT, [EMAIL PROTECTED] wrote:
>
> > Programmed a solution in Statistica Basic that transforms the raw
data
> > into the proper form for the "Logit" tool: codes and [frequency]
> > counts. Then, used the Logit tool to fit a curve to the data
> > using "maximum likelyhood" prediction method. Looked at the 2D
> > function plot and it looked reasonable. However, when I decrease
the
> > ration of ones to zeros (thus decreasing the probability) at the
> > beginning of the data set (time ordered), the function plot is way
off
> > in the center where there are entirely all ones. Is there a better
> > model to use? One that will not go "haywire" when data is changed
at
> > the beginning or end of the data set?
> >
> I answered before, but I don't know what you are talking about now.
>
> It sounds like you are discarding a bunch of your data, and that c
> consists of selectively discarding one response (the 1's); and then
> you are surprised when the model changes. I don't know if you are
> dropping too much data, or if a change depends on the nature of what
> you drop.
>
> I don't know, even, what you mean by, "beginning or end of the data
> set", in this context. When the data are ordered, in a meaningful
> way, then that is something that might become a factor --
> statistically speaking -- in the analysis.
>
> You might have to find someone to speak to, with your data in hand, in
> order to clear up those descriptions.
>
> --
> Rich Ulrich, [EMAIL PROTECTED]
> http://www.pitt.edu/~wpilib/index.html
>
I'll do some more digging and eventually get back to you, if and when I
find the answer. I have alot of questions that need answers that might
not be appropriate for this newsgroup. For example, can I get the
Logit tool (Statistica) to plot a 2D function for values beyond the
observed data of the independent variable?
Sent via Deja.com http://www.deja.com/
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