In an analysis of variance (ANOVA), cf. Chapter 9,
the contribution
of various parameters on the variance in scoring result is
determined, including the interaction of parameters. This is
carried out by dividing the values of the parameters in ranges or
levels. Thus each parameter p has levels 
. An M-dimensional space is defined by the Cartesian
product of the M parameters,
This space is divided into cell s 
, the
number of cells being
