A matrix with ncol(x)+1 columns, in which each row corresponds
to a missing data pattern (1=observed, 0=missing). Rows and columns are
sorted in increasing amounts of missing information. The last column and
row contain row and column counts, respectively.
Arguments
.data
Data frame. Missing values must be coded NA.
dependent
Character vector usually of length 1, name of depdendent
variable.
explanatory
Character vector of any length: name(s) of explanatory
variables.
rotate.names
Logical. Should the orientation of variable names on plot
should be vertical.
...
pass other arguments such as plot = TRUE to
md.pattern.