Table 3. Results of chest X-ray COVID-19 classification based on LWL-SOM.

Experiment No	Samples cases	Correlation coefficient	Mean absolute error	Root mean squared error	Relative absolute error	Root relative squared error	Total Number of Instances
		Locally weighted learning (LWL) with data clustering using self-organized mapping (SOM)
Experiment -1	Covid19 vs No finding	1	0	0	0%	0%	625
Experiment -2	Covid19 vs Pneumonia	0.9999	0.0018	0.0067	0.55%	1.6716%	625
Experiment -3	Pneumonia vs No finding	1	0	0	0%	0%	1000
Experiment -4	Covid19 vs No finding vs Pneumonia	0.9788	0.1009	0.2	11.3365%	21.1972%	1125