# 生成实验数据
set.seed(1234)smalldat <- data.frame(group1 = rep(1:2, each = 5), group2 = rep(c('a','b'), times = 5), x = rnorm(10))# convert to data.frame to data.tablelibrary(data.table)smalldat <- data.table(smalldat)# convert aggregated variable into raw data fileset.seed(1234)smalldat <- data.frame
