A data frame with 28 observations on the following 4 variables.
treatment
a factor with levels ABCDEFG
animal
a factor with levels A1A2A3A4A5A6A7
period
a factor with levels P1P2P3P4
response
a numeric vector
References
SAMPAIO, I. B. M. Estatistica aplicada a experimentacao animal. 3nd Edition. Belo Horizonte: Editora FEPMVZ, Fundacao de Ensino e Pesquisa em Medicina Veterinaria e Zootecnia, 2010. 264p.