Dear Stoet This can be handled well in using a mixed-effects model, library (nmle). You can use the lmList option to check whether the slopes differ across populations.
------ Harold C. Doran Director of Research and Evaluation New American Schools 675 N. Washington Street, Suite 220 Alexandria, Virginia 22314 703.647.1628 <http://www.edperform.net> -----Original Message----- From: Gijsbert Stoet [mailto:[EMAIL PROTECTED] Sent: Sunday, July 20, 2003 10:51 PM To: [EMAIL PROTECTED] Subject: [R] how to test whether two slopes are sign. different? Hi, suppose I do want to test whether the slopes (e.g. determined with lsfit) of two different population are significantly different, how do I test this (in R). Say for example, I found out what the slope between age and number of books read per year is for two different populations of subjects (e.g. 25 man and 25 woman), say using lsfit. How can I tell whether the slopes are different in R. (And how would I do it for regression coefficients?) Thanks a lot for your help. ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help
