Table 3. Normal distribution analysis (mean±std) of the combined mel-frequency cepstral coefficients (MFCCs) using the deep breathing dataset.

Category		Normal distribution analysis
		Combined MFCC values	Kurtosis	Skewness
COVID-19	Asymp.	-0.05±0.69	2.61±2.12	-0.17±0.97
	Mild	-0.15±0.63	6.63±6.51	0.91±4.95
	Moderate	0.04±0.58	2.54±1.12	-0.15±0.96
	Overall	-0.12±0.64	5.82±5.99	0.65±4.35
Healthy		0.12±0.60	3.23±6.06	-0.36±1.08
p-value		<0.001	0.941	0.014