[R] Fwd: Negbin Error Warnings

[Peter Ehlers]

Clara,

The most likely problem is that theta==0 for some of the
calculations. Or mu is NA, I suppose.

  -Peter Ehlers

milton ruser wrote:
> Dear Clara,
> 
> Thanks for the reply. I am forwarding your message to the list, ok.
> When I wrote was a way of get further information to help the helpers.
> 
> happy holidays,
> 
> milton
> 
> ---------- Forwarded message ----------
> From: Clara Brück <clara_brueck at web.de>
> Date: 2009/12/30
> Subject: Re: [R] Negbin Error Warnings
> To: milton ruser <milton.ruser at gmail.com>
> 
> 
> 
> 
> Dear Milton,
> 
> Thanks for your email. I ran the NBR-model and then tried to compute the
> first differences of some
> expected values:
> m3.x1 <-setx(m3, advisory=1)
> m3.x2 <-setx(m3, advisory=0)
> m3.s1 <-sim (m3,x=m3.x1, x1=m3.x2)
> 
> However, I then get 50 error warnings, and there all like this:
> In rpois(k, (mu * rgamma(k, theta))/theta) : NAs produced
> 
> 
> Bests
> Clara
> 
>> -----Ursprüngliche Nachricht-----
>> Von: "milton ruser" <milton.ruser at gmail.com>
>> Gesendet: 30.12.09 15:06:04
>> An: Clara Brück <clara_brueck at web.de>
>> CC: r-help at r-project.org
>> Betreff: Re: [R] Negbin Error Warnings
> 
> Dear Clara,
>> could you, please, share the summary() of your data.
>>
>> bests
>>
>> milton
>>
>> 2009/12/30 Clara Brück <clara_brueck at web.de>
>  > Hi,
>> I ran a negative binomial regression (NBR) using the Zelig-package
>> and the negbin model.
>> When I then try to use the simumlation approach using the setx () and
>> sim() functions to calculate expected values
>> and first difference for different levels of one of my independent
>> variables, I get 50 errors warnings, telling me that the calculation
>> rpois produced NAs. However, the data I use doesn't have any NAs.
>> Does this mean that the NBR-model is the wrong model for this data?
>>
>> Thanks in advance.
>>
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>>
>>
>>
> 
> 
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-- 
Peter Ehlers
University of Calgary
403.202.3921