Sokal and Rohlf (2012) describe an experiment to gauge the variability in wing length in female mosquitos (Aedes intrudens). Four females were randomly selected from three cages and two measurements were made on the left wing of each female. Both cage and female (in cage) can be seen as random effects.
data(mosquito)
A data frame with 24 observations on the following 4 variables.
length
Wing length in micrometers
cage
Cage number.
female
Female (in cage) number
measures
Measurement (in female in cage) number, i.e. pseudoreplicates in female.