Re: [R] Proportional response and boosting

2009-01-20 Thread Imelda.Somodi
Dear Gerard, Thank you very much for the quick answer. I am a bit uncertain, what you meant by total frequency of type A. I have data on the extent of type A at a location (let's call it freqA), this can be taken for fequency, yes and I have information on the total extent of all the nautral vege

Re: [R] Proportional response and boosting

2009-01-20 Thread Gerard M. Keogh
Quick response on the binomial: If possible I would suggest you should model pi = (number/freq of type A) / (total_freq of type A) veg.glm = glm ( pi ~ x, weights = total_freq, family=binomial) The glm method is supposed to work only on the natural numbers (inc 0!) but also works for decimal da

[R] Proportional response and boosting

2009-01-20 Thread Imelda.Somodi
Dear experts of boosting! I am planning to build vegetation models via boosting with either gbm or mboost. My problem is that my response variable is the proportion of a vegetation type in natural vegetation at a location. ResponseA = (area of vegetation type A/area of all natural vegetation ty