Table 1 Sample characteristics by COC group
|  | COC+  N = 35 | COC− N = 37 | Statistic | p-value |
|---|---|---|---|---|
Demographics | Â | Â | Â | Â |
 Age in years, M (SD) | 45.40 (6.45) | 43.03 (7.50) | t(70) = 1.44 | 0.156 |
 Male gender, n (%) | 21 (60%) | 21 (57%) | χ(1)2 = 0.08 | 0.780 |
 African-American race, n (%) | 28 (80%) | 28(76%) | χ(1)2 = 0.20 | 0.659 |
 Education in years, M (SD) | 12.54 (2.58) | 13.97 (2.03) | t(70) = 2.62 | 0.011 |
Other substance use in past 30Â days | Â | Â | Â | Â |
 Daily nicotine, n (%) | 21 (60%) | 12 (32%) | χ(1)2 = 5.51 | 0.019 |
 Any alcohol, n (%) | 30 (86%) | 20 (54%) | χ(1)2 = 8.50 | 0.004 |
 Any marijuana, n (%) | 16 (46%) | 10 (27%) | χ(1)2 = 2.72 | 0.099 |
 Number of substances used, M (SD) | 2.00 (0.77) | 1.14 (1.06) | t(70) = 3.95 |  < 0.001 |