Re: Statistical modeling of novel chemical systems( AKA Chemist with lots of stats questions)

On Tue, 2006-08-29 at 13:06 -0700, ghostwriter wrote:
Let me summerize.

I managed to figure out a good statistical model to one of the major
reactions in my work. Everyone is extremely happy with that fact,
except for the PhD that I bumped from this years call for papers.
Unfortunatly said PhD is also the official go to guy for stats
problems, and while he hasnt snubbed me completely getting my questions
answered has been pulling teeth.

I am trying to iterate in order to maximize the fit of my curve to the
data, but what equation should I use to determine when I have the best
fit? Maximizing for R^2 gives systematic weaknesses in the model due
to the fact that the reaction is exponential, so I don't wish the
points weighted equally thoughout the entire reaction. Ideally I want
to maximize the confidence intervals, and while getting enough repeats
for each time isnt difficult, the curve gives only a single data point
for each time so a T-test isnt possible.

The equation is

f(x)=exp(a*x^b)

a is always negative and b is usally between -1 and -2

f(x) is therefor always between 0 and 1 and approaches 1 as time goes
to infinity.

Any help greatly appreciated.

How were these things done before the introduction of computers?

--
Jeremy Boden


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