Number of failures of piston rings in three legs of four steam-driven compressors.
A two-way classification, see
The data are given in form of a
The table gives the number of piston-ring failures in each
of three legs of four steam-driven compressors located in the
same building. The compressors have identical design and are
oriented in the same way. The question of interest is whether
the two classification variables (compressor and leg) are independent.
S. J. Haberman (1973), The analysis of residuals in cross-classificed tables. Biometrics 29, 205–220.
data("pistonrings", package = "HSAUR") mosaicplot(pistonrings)