28.2 Anova test compares more than two groups

power.anova.test (groups = 3, between.var = var(means),
                  within.var = mean(sds*sds), sig.level = .05,
                  power = .8, n = NULL)

## 
##      Balanced one-way analysis of variance power calculation 
## 
##          groups = 3
##               n = 13
##     between.var = 476
##      within.var = 1210
##       sig.level = 0.05
##           power = 0.8
## 
## NOTE: n is number in each group