Improving an Intelligent Detection System for Coronary Heart Disease Using a Two-Tier Classifier Ensemble

Table 2

Summarization of each dataset’s characteristics and properties.

Dataset	# features	# instances	Ratio between normal and CHD
Z-Alizadeh Sani	54	303	1 : 2.5
Statlog	13	261	1 : 0.78
Cleveland	13	303	1 : 0.85
Hungarian	13	294	1 : 0.56