by CHOQUET » Tue Jul 07, 2009 3:08 am
Hello,
First select the number of age classes A that you need in DATA STATUS
The sentence in GEMACO is by default for capture:
firste+nexte
In most of the case firste is the first capture rate which should be fixed
to one. nexte modelize age for the recapture rate. For a quadratic effect then use the following sentence:
firste+nexte(1:A).[i+nexte*x(1)+nexte*x(2)]
where x(1) is the vector of covariates for a linear trend with age and
x(2) is the vector of covariates for a quadratic trend with age.
x(1) and x(2) must be defined in an external file with the following format
with A=4 (see the manual p 35)
2
4 4
1 2 3 4
1 4 9 16
Note that for large values of A, it is better to standardized covariates.
One you have defined this file, select the menu "file of external covariates"
in GEMACO interface.
Sincerely,
Rémi