Table 5.

Performance of MART-selected predictors in explaining response variation.

Response indicator	Model	Model-explained variation	Unexplained (random) variation	Model explained variation/group mean explained variation	p value for lack of fit to experimental group means	Model explained variation/total variation (R2)
ET-1	Experimental group means	39.0	66.9	1.00		0.36
	MART − all variables	32.9		0.84	0.83	0.31
	Main effects − 3 variables	25.7		0.66	0.02	0.24
	SO2	21.4		0.55		0.20
	NO2	6.5		0.17		0.06
	CO	0.7		0.02		<0.01
VEGF	Experimental group means	17.4	35.4	1.00		0.33
	MART − all variables	16.0		0.92	0.87	0.30
	Main effects − 3 variables	12.1		0.69	<0.01	0.23
	NH3	10.5		0.60		0.20
	NMVOOXY	2.6		0.15		0.05
	CO	0.4		0.02		<0.01
MMP3	Experimental group means	28.2	124.4	1.00		0.18
	MART − all variables	19.2		0.68	0.76	0.13
	Main effects − 3 variables	17.6		0.62	0.15	0.12
	NH3	12.7		0.45		0.08
	NMVOALKE	3.9		0.14		0.03
	NMVOOXY	4.4		0.15		0.03
MMP7	Experimental group means	112.2	445.9	1.00		0.20
	MART − all variables	36.6		0.33	0.25	0.07
	Main effects − 3 variables	37.7		0.33	0.33	0.07
	NH3	12.7		0.11		0.02
	VOALLI	22.9		0.20		0.04
	CARBDI	5.3		0.05		<0.01
MMP9	Experimental group means	145.3	110.3	1.00		0.57
	MART − all variables	135.7		0.93	0.99	0.53
	Main effects − 3 variables	116.2		0.80	0.04	0.45
	NH3	92.3		0.64		0.36
	SO2	42.0		0.29		0.16
	CO	< 0.01		<0.01		<0.01
TIMP2	Experimental group means	110.0	205.6	1.00		0.35
	MART − all variables	92.7		0.84	0.99	0.29
	Main effects − 3 variables	71.7		0.65	0.09	0.23
	NO2	40.5		0.37		0.13
	NO	26.2		0.23		0.08
	POHOP	10.6		0.10		0.03
HO-1	Experimental group means	123.3	400.5	1.00		0.24
	MART − all variables	77.7		0.63	0.93	0.15
	Main effects − 3 variables	26.7		0.22	0.13	0.05
	NH3	22.1		0.18		0.04
	NMVOHAL	3.2		0.03		<0.01
	CARBDI	2.6		0.02		<0.01
TBARS	Experimental group means	103.8	55.3	1.00		0.65
	MART − all variables	93.3		0.90	0.99	0.57
	Main effects − 3 variables	72.8		0.70	< 0.01	0.46
	SO2	35.0		0.34		0.21
	NO2	30.9		0.30		0.19
	NO	23.1		0.22		0.15