Table 2.

Number of cases after splitting using various nodule size criteria.

Splitting criteria	Cohort	Subset	Cancer	Noncancer	Total	Chi-square
Split by 6 and 16	C1	$<6$	14	43	57	76.172
		$\ge 6$ and $<16$	54	126	180
		$\ge 16$	17	7	24
	C2	$<6$	23	21	44	87.265
		$\ge 6$ and $<16$	43	123	166
		$\ge 16$	19	8	27
Split by 6	C1	$<6$	14	43	57	155.37
		$\ge 6$	71	133	204
	C2	$<6$	23	21	44	134.35
		$\ge 6$	62	131	193
Split by 6 and 8	C1	$<6$	14	43	57	35.92
		$\ge 6$ and $<8$ mm	7	65	72
		$\ge 8$	64	68	132
	C2	$<6$	23	21	44	27.51
		$\ge 6$ and $<8\mathrm{mm}$	19	64	83
		$\ge 8$	43	67	110

Note: Chi-square analysis: For split by 6 and 16 mm and 6 and 8 mm, $\mathrm{d}f=2$ and $p=0.05$, critical value is 5.991; for split by 6 mm only $\mathrm{d}f=1$ and $p=0.05$, critical value is 3.84. Here none of them are significant.