hello,

I want to  know as mortality in different families of epiphytes after selective logging in the forest
I want to make a survival analysis with left and right censored data.  My study begins in 2004 but I have many individuals who enter the study in 2007
I have tried this:
                    surara<-survfit(Surv(fecha,estado)~categoria)
fecha= time 

estado= dead
categoria= control and experimental

but it is working just with right censored data
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