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I am interested in including TT in my models since it has worked well in my abundance models in MARK. I noted that the overview for secr indicates that a "timecov" argument may be used. However, I am unfamiliar with how to set that up and then code for it. Would someone be willing to share code where they have included TT so that I can see how to add it to my own models?

Thank you!

Sorry, but can you please tell me what TT means save me the trouble of looking up MARK?
Murray

Of course. TT is a quadratic model of time. When I code for it in MARK, in the design matrix, I need to include two columns. This would be for five sessions:

T TT
1 1
2 2
3 4
4 8
5 16

Would something like this work?

secrsexandTT <- secr.fit(myCH, model = (g0 ~ g+T), groups = 'sex', buffer=6000, timecov=c(1,2,4,8,16))

Thank you again!

I see. Strictly, your code won't work as you intend because in 'secr' T refers to the 'built-in' covariate 1,2,3,4,5, and your model formula doesn't actually use the quadratic variable in timecov. For a true quadratic model you could use

Code: Select all

secrsexandTT <- secr.fit(myCH, model = (g0 ~ g+t1+t2), groups = 'sex', buffer = 6000,
    timecov = data.frame(t1 = 1:5, t2 = (1:5)^2))


(note the need to include both the linear and squared values as in the MARK design matrix).
Murray

Thank you! That is great!