An embedded and charset-unspecified text was scrubbed... Name: not available URL: <https://stat.ethz.ch/pipermail/r-sig-ecology/attachments/20120413/29deffb1/attachment.pl>
Which function would fit these data (Version 2)
3 messages · Beutel, Terry S, Bob OHara, David L Lorenz
On 04/13/2012 06:16 AM, Beutel, Terry S wrote:
Hi list members Sending this again as symbols in the previous version did not translate. Apologies if this is not too specifically R related, but I am looking fit a model to some simulated data. X is distance to sample point, y is binary outcome (present/absent). I was hoping someone can suggest a (presumably) non linear function that might meet the following criteria A. 0<= y<=1 (actual responses are binary) B. xmax = infinity C. xmin<= 0 D. Where x = 0 then y>= 0 E. Where x equals Infinity then y equals 1 F. As x approaches Infinity from xmin, the slope of the function declines monotonically toward 0.
my initial reaction was to think "logistic regression", but my experience with questions like this is that we'll save a lot of time if you explain the context. BTW, I'm not sure why you want "the function" to decrease to zero when x approaches infinity when at the same time y should equal 1 at infinity. It's not a big problem, though. Just use 1-y instead of y. Bob
Bob O'Hara Biodiversity and Climate Research Centre Senckenberganlage 25 D-60325 Frankfurt am Main, Germany Tel: +49 69 798 40226 Mobile: +49 1515 888 5440 WWW: http://www.bik-f.de/root/index.php?page_id=219 Blog: http://blogs.nature.com/boboh Journal of Negative Results - EEB: www.jnr-eeb.org
An embedded and charset-unspecified text was scrubbed... Name: not available URL: <https://stat.ethz.ch/pipermail/r-sig-ecology/attachments/20120413/d46e8b1a/attachment.pl>