Donald Burrill <[EMAIL PROTECTED]> wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > Look in your favorite ANOVA text for the chapter on post hoc comparisons, > and in particular the method of Scheffe' (called in some texts the > "S-method"). The linear combination you describe is properly called a > "contrast" in this context, a contrast being merely a linear combination > of means with the constraint that the coefficients of the means sum to 0 > (as your +0.5, +0.5, -1.0 do).
A contrast needn't be a post hoc comparison. Often a particular contrast is the primary comparison of interest right from the start. In that circumstance, the Scheffe thing won't be appropriate. Glen . . ================================================================= Instructions for joining and leaving this list, remarks about the problem of INAPPROPRIATE MESSAGES, and archives are available at: . http://jse.stat.ncsu.edu/ . =================================================================
