Regression deals with the prediction of a value, rather than a class. Given values
for a set of variables, X1, X2, . . . , Xn, we wish to predict the value of a variable
Y. For instance, we could treat the level of education as a number and income as
another number, and, on the basis of these two variables, we wish to predict the
likelihood of default, which could be a percentage chance of defaulting, or the
amount involved in the default.