Anova
n <- 1000
set.seed(123)
x <- rnorm(n, 1)
y <- rnorm(n, 1.2)
z <- rnorm(n, 1.1)
dat <- data.frame(outcome = c(x,y,z),
group = rep(c("X","Y","Z"), each = n))
fit <- aov(outcome ~ group, data = dat)
summary(fit)
## Df Sum Sq Mean Sq F value Pr(>F)
## group 2 27.2 13.621 13.8 1.08e-06 ***
## Residuals 2997 2957.1 0.987
## ---
## Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
PostHoc Test
TukeyHSD(fit, ordered = TRUE)
## Tukey multiple comparisons of means
## 95% family-wise confidence level
## factor levels have been ordered
##
## Fit: aov(formula = outcome ~ group, data = dat)
##
## $group
## diff lwr upr p adj
## Z-X 0.06375961 -0.04040611 0.1679253 0.3228639
## Y-X 0.22633739 0.12217168 0.3305031 0.0000011
## Y-Z 0.16257778 0.05841207 0.2667435 0.0007505