Untitled

help(birthwt)

## No documentation for 'birthwt' in specified packages and libraries:
## you could try '??birthwt'

library(MASS)
dat <- MASS::birthwt
birthwt$race <- c("White", "Black","Other")[birthwt$race]
aggregate(bwt ~ race, length, data=dat)

##   race bwt
## 1    1  96
## 2    2  26
## 3    3  67