Hi, Given the following,
a <- rnorm(5) b <- rnorm(5) c <- rnorm(5) a.1g.scale <- scale(c(a,b,c))[1:5] b.1g.scale <- scale(c(a,b,c))[6:10] c.1g.scale <- scale(c(a,b,c))[11:15] a.2g.scale <- scale(c(a,b))[1:5] b.2g.scale <- scale(c(a,b))[6:10] c.2g.scale <- scale(c) a.3g.scale <- scale(a) b.3g.scale <- scale(b) c.3g.scale <- scale(c) I am puzzled why the p-values are identical for t.test(a.1g.scale, b.1g.scale), t.test(a.2g.scale, b.2g.scale), and t.test(a, b); similarly for t.test(a.3g.scale, b.3g.scale) and t.test(b.3g.scale, c.3g.scale); similarly for t.test(b.1g.scale, c.1g.scale) and t.test(b, c) > t.test(a.1g.scale, b.1g.scale)$p.value [1] 0.7462252 > t.test(a.2g.scale, b.2g.scale)$p.value [1] 0.7462252 > t.test(a.3g.scale, b.3g.scale)$p.value [1] 1 > t.test(b.1g.scale, c.1g.scale)$p.value [1] 0.4995508 > t.test(b.2g.scale, c.2g.scale)$p.value [1] 0.885622 > t.test(b.3g.scale, c.3g.scale)$p.value [1] 1 > t.test(a, b)$p.value [1] 0.7462252 > t.test(b, c)$p.value [1] 0.4995508 [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.