--- Maritza <[email protected]> wrote:
> Somebody knows how to program a logistic distribution in Intercooled
> Stata 8.2 for Non-Linear Squares?. Stata offers two logistic
> functions but I need to apply this one: Y = 1/(1+exp(-b*X))
> I've tried to use the -User-supplied function- in the Non-Linear
> Statistics and every time I got an error message "varlist required"
> which could be because I have more than one explanatory variable (I
> tried with just one, same error message)or because I need an specific
> indication that my data is longitudinal.
> This is what I typed:
>
> nl Y = 1/(1+exp(-b*X)) iitt avgtarif pdit tot lavrgdp lrdgpdif
> ldistancia (the first one is the dependent variable)
why don't you just use -glm-? -glm iitt avgtarif pdit tot lavrgdp
lrdgpdif ldistancia, family(binomial) link(logit)- will fit that model
with maximum likelihood. If the dependent variable is a continuous
variable (e.g. a proportion) than you will also need to add the option
scale(x2) or the option robust to get correct standard errors.
Alternatively, you could use -betafit-, see:
http://home.fsw.vu.nl/m.buis/software/betafit.html for various
recources on that.
Hope this helps,
Maarten
-----------------------------------------
Maarten L. Buis
Department of Social Research Methodology
Vrije Universiteit Amsterdam
Boelelaan 1081
1081 HV Amsterdam
The Netherlands
visiting address:
Buitenveldertselaan 3 (Metropolitan), room Z434
+31 20 5986715
http://home.fsw.vu.nl/m.buis/
-----------------------------------------
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