Table 3.

Nasal group of 40 cases.

Geometric feature definition	The first geometric feature			The second geometric feature		The third geometric feature			The fourth geometric feature
	Surface-volume ratio			Mean airway width		Nostril area size			Intake Angle
Grouping Method	standard normal distribution			The ratio is roughly 1:1		standard normal distribution			The ratio is roughly 1:1
Group name	a1	a2	a3	b1	b2	c1	c2	c3	d1	d2
Count of Scores	6	28	6	20	20	6	28	6	20	20
Group Definition	less than 0.565	between 0.565 and 0.878	greater than 0.878	less than 1.8 mm	greater than 1.8 mm	less than 40mm2	between 40 and 111mm2	greater than 111mm2	greater than 60°	less than 60°