On Tue, 4 Aug 2009 09:46:17 -0700, Dragos Zaharescu <[email protected]> wrote:
>I run discriminant analysis on a dataset with plants speci >Hi all, >I run discriminant analysis on a dataset with plants species presence as >variables (binary, independent) and lakes # as cases. I also have a >classification variable with 4 classes. Assuming you apply "ordinary" discriminant analysis, you are violating the homogeneity assumption if you apply DA on binary data. See Chapter 14 in Zuur et al (2007) "Analysing Ecological Data", for all 10-ish assumptions of DA. >I have some problems in interpreting Fisher's classification function >coefficients. >It is said that a case belongs to the class for which the score is highest. No..that is wrong as well...see the same chapter. It is about the distance of a point to the centroids. Alain Dr. Alain F. Zuur First author of: 1. Analysing Ecological Data (2007). Zuur, AF, Ieno, EN and Smith, GM. Springer. 680 p. URL: www.springer.com/0-387-45967-7 2. Mixed effects models and extensions in ecology with R. (2009). Zuur, AF, Ieno, EN, Walker, N, Saveliev, AA, and Smith, GM. Springer. http://www.springer.com/life+sci/ecology/book/978-0-387-87457-9 3. A Beginner's Guide to R (2009). Zuur, AF, Ieno, EN, Meesters, EHWG. Springer http://www.springer.com/statistics/computational/book/978-0-387-93836-3
