Table 2: The original decision table of patients’ symptoms.

Body TemperatureDry coughHeadacheInfluenza

111111
211011
321001
42011
52011
62010
721111
83011
93010
1031101

Note: in the table, body temperature : 1 means high, 2 means slightly higher, and 3 means normal; for dry cough , headache , influenza : 1 means yes and 0 means no.