Table 2.
Primary Substance Use Between Groups
| Substance | Statistic | Marijuana Group | Cocaine Group | Test Statistic, p-value |
|---|---|---|---|---|
| Marijuana Use in Past 30 Days | N | 50 | 153 | |
| Mean (SD) | 27.26 (6.5) | 3.51 (7.57) | WRS=8657, p<.001 | |
| Median (IR) | 30 (0) | 0 (2) | ||
| Marijuana Years | N | 50 | 153 | |
| Mean (SD) | 16.78 (9.4) | 11.13 (9.07) | WRS=6297, p=.001 | |
| Median (IR) | 13 (12) | 10 (17) | ||
| Cocaine Use in Past 30 Days | N | 50 | 153 | |
| Mean (SD) | .28 (1.16) | 9.48 (7.7) | WRS=1714, p<.001 | |
| Median (IR) | 0 (0) | 8 (8) | ||
| Cocaine Years | N | 50 | 153 | |
| Mean (SD) | 1.12 (1.9) | 10.8 (6.8) | WRS=1666, p<.001 | |
| Median (IR) | 0 (2) | 10 (10) | ||
| Alcohol Use in Past 30 Days | N | 50 | 154 | |
| Mean (SD) | 5.9 (6.94) | 7.14 (8.12) | WRS=4893.5, p=.52 | |
| Median (IR) | 4 (8) | 4 (11) | ||
| Alcohol Years: Controlling for Age | N | 50 | 154 | |
| LSMeans (SE) | 14.26 (1.08) | 15.64 (.52) | ANCOVA1, Z=1.15, p=.25 |
WRS=Wilcoxon Rank Sum
1
Z-value for the Wald test using generalized estimating equations to correct the standard error for heteroscedasticity in the residuals