TABLE 4. Classification Performance of HHO-FKNN in Terms of ACC, MCC, Sensitivity, and Specificity.

Fold	Optimal features	ACC	MCC	Sensitivity	Specificity
No.1	{F2, F3, F4, F5, F8, F11, F13, F14, F16, F19, F20, F24, F26, F27, F31}	1.0000	1.0000	1.0000	1.0000
No.2	{F2, F3, F4, F6, F8, F10, F11, F14, F15, F16, F17, F19, F20, F27, F30, F31}	0.8000	0.6124	0.5000	1.0000
No.3	{F2, F3, F4, F5, F6, F7, F8, F9, F13, F16, F22, F23, F28, F29, F30, F31}	1.0000	1.0000	1.0000	1.0000
No.4	{F2, F3, F4, F5, F6, F7, F8, F10, F14, F15, F20, F29, F30}	1.0000	1.0000	1.0000	1.0000
No.5	{F2, F3, F4, F5, F6, F8, F13, F17, F18, F20, F22, F24, F25, F27, F30}	1.0000	1.0000	1.0000	1.0000
No.6	{F2, F4, F8, F11, F14, F15, F18, F20, F23, F27, F30}	1.0000	1.0000	1.0000	1.0000
No.7	{F2, F3, F5, F6, F7, F8, F11, F12, F13, F14, F20, F25, F26, F28, F30}	0.8000	0.6124	0.5000	1.0000
No.8	{F2, F3, F4, F6, F7, F8, F9, F11, F13, F15, F16, F18, F20, F24, F26, F31}	1.0000	1.0000	1.0000	1.0000
No.9	{F2, F3, F8, F10, F12, F14, F21, F23, F26, F30}	1.0000	1.0000	1.0000	1.0000
No.10	{F2, F3, F4, F11, F14, F15, F16, F19, F25, F27, F28, F29, F30}	1.0000	1.0000	1.0000	1.0000
AVG.	–	0.9400	0.8891	0.9000	0.9667
STD	–	0.0966	0.1791	0.2108	0.1054