Table 2.

Confusion matrix for the rule-based classifier with four decision classes. The number of samples in each class is shown in parenthesis

Observed class	Classified as
	Fetus	Age 0–4	Age 5–27	Age 28 plus	Accuracy per class
Fetus (30)	30	0	0	0	100 %
Age 0–4 (12)	0	12	0	0	100 %
Age 5–27 (21)	0	2	13	6	62 %
Age 28 plus (45)	0	1	1	43	95.5 %
Model accuracy					90 %