I'm afraid ANCOVA is the way to go. It shouldn't be cumbersome though, not in any up-to-date software. If you have three columns of data (two continuous, one categorical), and specify one of the continuous as the dependent and the other two as predictors, then almost all software packages will do an ANCOVA.
Gareth Russell On Wed, 31 Mar 2010 11:02:07 -0400, Howie Neufeld <[email protected]> wrote: >Dear All - I have a stats question concerning comparing linear >regressions. If you have two or more regressions, and want to know if >their slopes and/or intercepts are significantly different, what >procedure would you use? I am familiar with SAS mainly. Zar has a >two-sample t-test equivalent for comparing two slopes, but the procedure >for intercepts is extremely cumbersome, as is the multiple slope >comparison, which involves ANOCOVA. > Thanks! >Howie Neufeld > >-- >Dr. Howard S. Neufeld, Professor >Department of Biology >572 Rivers Street >Appalachian State University >Boone, NC 28608 > >email: [email protected] >departmental webpage: http://www.biology.appstate.edu/faculty/neufeldhs.htm >personal webpage: http://www.appstate.edu/~neufeldhs/index.html > >Tel: 828-262-2683 >Fax: 828-262-2127 >=========================================================== ==============
