Not sure why you feel the need to use gnm here - are you working with non-normal data? From your description it would seem that nls is more appropriate, Heather Dr H Turner Research Fellow Dept. of Statistics The University of Warwick Coventry CV4 7AL
Tel: 024 76575870 Fax: 024 76524532 Url: www.warwick.ac.uk/go/heatherturner ________________________________ From: Ronaldo Prati [mailto:[EMAIL PROTECTED] Sent: Thu 14/12/2006 13:41 To: r-help@stat.math.ethz.ch Subject: [R] Model formula question Hi all, I'm not familiar with R programming and I'm trying to reproduce a result from a paper. Basically, I have a dataset which I would like to model in terms of successive increments, i.e. (y denote empirical values of y) y_1 = y1, y_2 = y1 + delta1, y_3 = y1 + delta1 + delta2. .. y_m = y1 + sum_2^m delta j where delta_j donote successive increments in the y-values, i.e. delta j = y_j - y_(j-1). In order to estimate y-values, I'm assuming that delta j is approximately equal to kj**u, such that my regression model should be something like this: ^y_1 = a1 ^y_2 = a1 + k2**u ^y_3 = a1 + k2**u + k3**u .. ^y_m = a1 + k2**u + k3**u + ... + km**u or, generically ^yi = a1 + k * sum_j=2^i j**u and I need to fit a non-linear least-squares regression model to find the tripplet a1,k,u. I had a look to the gnm package, but I don't have the lesser idea how to formulate this problem to use this package. Can someone help me with that? cheers, Ronaldo [[alternative HTML version deleted]] ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
