In article <[EMAIL PROTECTED]>, Robert Lundqvist <[EMAIL PROTECTED]> wrote: >I found in one of the textbooks we use that calculating correlation >coefficients is not meaningful when you have categorical data. However, >using dummy variables should be possible, shouldn't it? Either when you >have one ordinary numerica variable and one dummy, or even when you have >two dummy variables. If not, could someone please put me in the right >direction so I can stop be so hesitating in class...Comments are welcome, >even if it turns out that I should have understood this.
Correlations are rarely appropriate, but regressions are. It means something that the effect of the dichotomous variable is something; it does not mean anything that it has a correlation of whatever with the variable being explained. Not only is normality not the rule, but it is not at all common. Standardization and transformations complicate the theory greatly. -- This address is for information only. I do not claim that these views are those of the Statistics Department or of Purdue University. Herman Rubin, Department of Statistics, Purdue University [EMAIL PROTECTED] Phone: (765)494-6054 FAX: (765)494-0558 . . ================================================================= Instructions for joining and leaving this list, remarks about the problem of INAPPROPRIATE MESSAGES, and archives are available at: . http://jse.stat.ncsu.edu/ . =================================================================
