```
#### Example 1: one-way ANOVA ####
outcome <- c(1.4,2.1,3.0,2.1,3.2,4.7,3.5,4.5,5.4) # data
treatment1 <- factor(c(1,1,1,2,2,2,3,3,3)) # grouping variable
anova1 <- aov(outcome ~ treatment1) # run the ANOVA
summary(anova1) # print the ANOVA table
EtaSq(anova1) # effect size
#### Example 2: two-way ANOVA ####
treatment2 <- factor(c(1,2,3,1,2,3,1,2,3)) # second grouping variable
anova2 <- aov(outcome ~ treatment1 + treatment2) # run the ANOVA
summary(anova2) # print the ANOVA table
EtaSq(anova2) # effect size
#### Example 3: two-way ANOVA unbalanced cell sizes ####
#### data from Maxwell & Delaney, 2004 ####
#### Designing experiments and analyzing data ####
dfMD <- data.frame(IV1=factor(rep(1:3, c(3+5+7, 5+6+4, 5+4+6))),
IV2=factor(rep(rep(1:3, 3), c(3,5,7, 5,6,4, 5,4,6))),
DV=c(c(41, 43, 50), c(51, 43, 53, 54, 46), c(45, 55, 56, 60, 58, 62, 62),
c(56, 47, 45, 46, 49), c(58, 54, 49, 61, 52, 62), c(59, 55, 68, 63),
c(43, 56, 48, 46, 47), c(59, 46, 58, 54), c(55, 69, 63, 56, 62, 67)))
# use contr.sum for correct sum of squares type 3
dfMD$IV1s <- C(dfMD$IV1, "contr.sum")
dfMD$IV2s <- C(dfMD$IV2, "contr.sum")
dfMD$IV1t <- C(dfMD$IV1, "contr.treatment")
dfMD$IV2t <- C(dfMD$IV2, "contr.treatment")
EtaSq(aov(DV ~ IV1s*IV2s, data=dfMD), type=3)
EtaSq(aov(DV ~ IV1t*IV2t, data=dfMD), type=1)
#### Example 4: two-way split-plot ANOVA -> EtaSq.aovlist ####
DV_t1 <- round(rnorm(3*10, -0.5, 1), 2)
DV_t2 <- round(rnorm(3*10, 0, 1), 2)
DV_t3 <- round(rnorm(3*10, 0.5, 1), 2)
dfSPF <- data.frame(id=factor(rep(1:(3*10), times=3)),
IVbtw=factor(rep(LETTERS[1:3], times=3*10)),
IVwth=factor(rep(1:3, each=3*10)),
DV=c(DV_t1, DV_t2, DV_t3))
spf <- aov(DV ~ IVbtw*IVwth + Error(id/IVwth), data=dfSPF)
EtaSq(spf, type=1, anova=TRUE)
```

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