Doug wrote: > I have a "meta-theorem" that the only quantity actually calculated according > to the formulas given in introductory texts is the sample mean. R> x <- c(1e-20, 1, -1) R> (x[1] + x[2] + x[3])/3 [1] 0 R> (x[3] + x[2] + x[1])/3 [1] 3.333333e-21 R> mean(x) [1] 0 Looks like he's right! Kevin