Syntax: DATA list of variables
The DATA command has two purposes. Its primary purpose is to introduce a
list of variables which are to be read by a subsequent READ command.
length of the variables is determined dynamically from the data introduced by
the READ command. All variables are read as covariates; they can be
converted to factors by the FACTOR command or transformed by the TRANSFORM
The variables to be read will normally include the following:
A case variable. This gives the case number of the observation. By default,
this is taken to be the first variable given in the list of variables, but
this may be over-ridden by using the CASE command.
A y-variable, taking the values 0 and 1 only for a binary model, or
non-negative integer values for a Poisson model.
A set of covariates and factors.
If the command is used more than once in a SABRE session, the second and
subsequent uses will introduce a new dataset to be analysed, and will also
clear the workspace, delete all model fitting information and reset the model
constants to their default values, preparing the program for an entirely new