Unweighted				Weighted
	Researc Part.	Non- Part.	Pct. Bias	p	Research Part.	Non- Part.	Pct. Bias	Pct. Bias Reduction	p
Native American	0.06	0.05	3.70	0.32	0.06	0.06	0.00	99.20	1.00
Latino	0.19	0.23	−9.40	0.02	0.19	0.19	−0.30	96.40	0.94
Black	0.19	0.17	4.10	0.28	0.19	0.19	−0.40	89.90	0.93
Asian American	0.16	0.13	8.20	0.03	0.16	0.16	1.10	86.50	0.83
Sex: Female	1.58	1.64	−11.30	0.00	1.58	1.60	−2.50	77.70	0.61
Income	8.69	8.44	7.80	0.04	8.69	8.70	−0.30	95.70	0.95
Mother’s education	5.71	5.29	21.70	0.00	5.71	5.74	−1.50	93.00	0.75
High school GPA	7.32	6.87	39.30	0.00	7.31	7.28	3.50	91.20	0.43
HS years studying math	6.08	5.99	16.50	0.00	6.08	6.08	0.40	97.70	0.94
Composite SAT (100)	12.78	11.84	53.90	0.00	12.78	12.74	1.70	96.80	0.72
Summer research participation	1.19	1.11	24.00	0.00	1.19	1.19	0.00	100.00	1.00
Came to college to prepare for     graduate/professional     school	2.66	2.78	22.80	0.00	2.78	2.74	7.10	68.70	0.03
Aspiration for a Ph.D.	0.35	0.24	26.30	0.00	0.35	0.35	0.30	98.80	0.95
Aspiration for a medical degree	0.33	0.28	10.30	0.01	0.33	0.33	−0.20	98.00	0.97
Life sciences major	0.38	0.30	16.30	0.00	0.38	0.38	0.70	96.00	0.90
Engineering/Computer science     major	0.24	0.27	−6.80	0.08	0.24	0.24	0.40	93.80	0.93
Physical sciences major	0.15	0.08	21.90	0.00	0.15	0.15	0.80	96.30	0.88
Health sciences major	0.20	0.23	−7.60	0.05	0.20	0.20	−0.20	97.40	0.97

Source: Mean comparison test of 2004 CIRP Freshman Survey and 2008 College Senior Survey data before and after statistically adjusting the sample with weights calculated from estimated propensity scores.