davebraze

library(dplyr)

## Toy data
df <- data_frame(block=rep(1:3, each=4), item=rep(1:4,3),
                 cond=rep(LETTERS[1:2], 6),
                 stim=paste0(rep(letters[1:2],6), rep(1:6,each=2)))

## Randomize blocks and trials within blocks
df.rand <- df %>%
    group_by(block) %>%