IF . . . . . . THEN class = 1
with an empty left-hand side and expand it progressively to
IF X = large . . . . . . THEN class = 1
IF X = large AND Z < 124.7 . . . . . . THEN class = 1
Dealing with Large Volumes of Data 195
IF X = large AND Z < 124.7 AND Q < 12.0 . . . . . . THEN class = 1
IF X = large AND Z < 124.7 AND Q < 12.0 AND M = green
THEN class = 1