Date:         Tue, 30 Jul 1996 21:06:42 -0300
Reply-To:     Silvano <silvano@UEL.BR>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         Silvano <silvano@UEL.BR>
Subject:      ZIP Models and NLMIXED - correction
Content-Type: multipart/alternative;

Use 

fact(y) and not lgamma(y+1).

Silvano.



/******************************************************
* Conjunto de dados usado no artigo de Ridout, Hinde *

* e Demétrio, Biometrics, 57, 219-223 (Março/2001) *

*******************************************************/

Data zip;

input y n;

datalines;

0 182

1 41

2 12

3 2

4 2

5 0

6 0

7 1

;

run;

Proc nlmixed data=zip;

parms p_0 = 0.1 lambda=1;

if y=0 then prob = p_0 +(1-p_0)*exp(-lambda);

else prob = (1-p_0)*exp(-lambda)*(lambda**y)/(fact(y));

loglike = log(prob);

model y ~ general(loglike);

run;

title;








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