The three gamma-ray burst (GRB) classes identified by statistical clustering analysis [7] are examined using the pattern recognition algorithm C4.5 [8]. Although the statistical existence of Class 3 (intermediate duration, intermediate fluence, soft) is supported, the properties of this class do not need to arise from a distinct source population. Class 3 properties can easily be produced from Class 1 (long, high fluence, intermediate hardness) by a combination of measurement error, hardness/intensity correlation, and a newly-identified BATSE bias (the fluence duration bias). Class 2 (short, low fluence, hard) does not appear to be related to Class 1. ©2000 American Institute of Physics.