[R] Binomial Reponses

Peter Dalgaard BSA p.dalgaard at biostat.ku.dk
Fri Oct 22 15:12:00 CEST 1999

R.E.Darnell at newcastle.ac.uk (R.E. Darnell) writes:

> I understand that there are two ways to define the response  for 
> binomial case in R(S). 
> 1) As a vector of p's for which the number of trials is assumed
>    to be 1
> 2) As a 2 column matrix, the first being the number of sucesses, the 
> second being the number of failures.

3) as a vector of p's, the number of trials given in the weights=

> Two questions I have concern the 2nd case.
> Does the model.response function convert the number of successes
>  into a propn? I couldn't see that it did.

Nope. That's not it's job. It just pulls out the relevant bits of the
model frame.
> and  how is the denominator  included as a (prior) weight?

Have a look at the initialize expression as defined in binomial().

   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)             FAX: (+45) 35327907
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