The dataset simulated2factor.xls or .txt contains 6 columns
representing variables x1-x6 generated by the computers for 300
individuals from some true model.  You are not told what the model is
and are asked in the homework to determine the structure.

Note that since this data is not from a real life example, all your
decisions about modeling it will be based completely on empirical
evidence.  Remember though that if this were real data, you would also
use the scientific knowledge about the subject area to help guide your
modeling decision.