data(Cichlids)
str(Cichlids)
if (require(Hmisc)) {
  summary(preference ~ genotype, Cichlids, fun = favstats)
} else {
  aggregate(preference ~ genotype, Cichlids, FUN = favstats)
}
if (require(plyr)) {
ddply(Cichlids, .(genotype),
  function(df)c(mean = mean(df$preference),
                standard.deviation = sd(df$preference),
                n = length(df$preference)))
}Run the code above in your browser using DataLab