http://commres.net/ 2026-04-07T18:17:03+00:00 http://commres.net/ http://commres.net/_media/wiki/logo.png text/html 2025-12-09T23:16:44+00:00 Anonymous (anonymous@undisclosed.example.com) http://commres.net/anova_note/code01?rev=1765322204&do=diff rm(list=ls()) rnorm2 <- function(n,mean,sd) { mean+sd*scale(rnorm(n)) } ss <- function(x) { sum((x-mean(x))^2) } set.seed(10) n <- 30 n.o <- n.p <- n o <- rnorm(n.o, 100, 10) p <- rnorm(n.p, 104, 10) # old way m.o <- mean(o) m.p <- mean(p) df.o <- n.o - 1 df.p <- n.p - 1 diff <- m.o - m.p m.o m.p diff pv <- (ss(o)+ss(p))/(df.o+df.p) se <- sqrt((pv/n.o) + (pv/n.p)) t.cal <- diff/se t.cal pt(t.cal, df.o+df.p) * 2 t.out <- t.test(o, p, var.equal=T) t.out t.out$statistic t.out$p.value # com… text/html 2025-12-05T15:05:31+00:00 Anonymous (anonymous@undisclosed.example.com) http://commres.net/anova_note/code02?rev=1764947131&do=diff # # ANOVA test with 4 levels in IV # rm(list=ls()) rnorm2 <- function(n,mean,sd){ mean+sd*scale(rnorm(n)) } ss <- function(x) { sum((x-mean(x))^2) } set.seed(11) n <- 31 na <- nb <- nc <- nd <- n mean.a <- 98 mean.b <- 99 mean.c <- 102 mean.d <- 103 A <- rnorm2(na, mean.a, sqrt(900/(na-1))) B <- rnorm2(nb, mean.b, sqrt(900/(nb-1))) C <- rnorm2(nc, mean.c, sqrt(900/(nc-1))) D <- rnorm2(nd, mean.d, sqrt(900/(nd-1))) ss(A) var(A) # A combined group with group A and B # We call it group total… text/html 2025-12-09T22:54:22+00:00 Anonymous (anonymous@undisclosed.example.com) http://commres.net/anova_note/output01?rev=1765320862&do=diff > > rm(list=ls()) > rnorm2 <- function(n,mean,sd) { + mean+sd*scale(rnorm(n)) + } > ss <- function(x) { + sum((x-mean(x))^2) + } > set.seed(10) > n <- 30 > n.o <- n.p <- n > o <- rnorm(n.o, 100, 10) > p <- rnorm(n.p, 104, 10) > > t.out <- t.test(o,p, var.equal=T) > t.out Two Sample t-test data: o and p t = -2.6941, df = 58, p-value = 0.009216 alternative hypothesis: true difference in means is not equal to 0 95 percent confidence interval: -11.012446 -1.623742 sample estimates: mea… text/html 2025-12-05T15:07:09+00:00 Anonymous (anonymous@undisclosed.example.com) http://commres.net/anova_note/output02?rev=1764947229&do=diff output > # > # ANOVA test with 4 levels in IV > # > rm(list=ls()) > rnorm2 <- function(n,mean,sd){ mean+sd*scale(rnorm(n)) } > ss <- function(x) { + sum((x-mean(x))^2) + } > > set.seed(11) > n <- 31 > na <- nb <- nc <- nd <- n > mean.a <- 98 > mean.b <- 99 > mean.c <- 102 > mean.d <- 103 > > A <- rnorm2(na, mean.a, sqrt(900/(na-1))) > B <- rnorm2(nb, mean.b, sqrt(900/(nb-1))) > C <- rnorm2(nc, mean.c, sqrt(900/(nc-1))) > D <- rnorm2(nd, mean.d, sqrt(900/(nd-1))) > ss(A) [1] 900 > var(A…