Path: news.mathworks.com!not-for-mail
From: "Tom Lane" <tlane@mathworks.com>
Newsgroups: comp.soft-sys.matlab
Subject: Re: glmfit binomial-probit with natural mortality
Date: Mon, 29 Sep 2008 14:36:25 -0400
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Joe or Bego, I'm not aware of what standard mathematical/statistical 
approach that is generally used here.  I could guess that it might involve 
estimating a non-zero baseline probability of response, with the link 
function describing how the probability increases.  But I really don't know.

I guess what I'm asking is this.  Are you looking for the right approach, or 
do you know the approach and you're looking for advice on how to do it in 
MATLAB?

-- Tom

"Villamide Bego" <bvillamide@gmail.com> wrote in message 
news:gbqs61$9ts$1@fred.mathworks.com...
> Hi Joe,
>
> I have the same problem as you. Have you any solution to this question?
>
> Thanks in advance.
>
> Bego.
>
>
>
> "Joe Ercolino" <joe_ercolino@hotmail.com> wrote in message 
> <g6vilo$h12$1@fred.mathworks.com>...
>> Hi
>>
>> I'm trying to fit a generalized linear model (GLM) with the
>> glmfit function. My problem deals with the
>> dose-response(Mortality)of a population of animals exposed
>> to a toxic agent. The most common models for this type of
>> regression use the binomial distribution and probit or logit
>> as link functions with the log(Dose) as predictors. The data
>> I'm working with shows a non zero response for the controls
>> (dose equal to zero). I think that the logit or probit
>> functions can not accommodate for this type type behavior
>> since they go from zero to one. Is there a way to make
>> glmfit to take into account the controls correction (natural
>> mortality) or there is any other feasible way to do it in
>> MATLAB?
>>
>> Thanks in advance.
>