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. Author manuscript; available in PMC: 2017 Aug 4.
Published in final edited form as: Drug Alcohol Depend. 2014 May 13;141:27–33. doi: 10.1016/j.drugalcdep.2014.04.028

Table 4.

Correlations between income1, cocaine-supply related2, cocaine-purchasing3, and cocaine-use4 variables.

Total income
quartile1
Number
of suppliers2
Unit price2 Cocaine
purity2
Cocaine
expenses3
Weekly
purchases3
Purchase
time3
Purchase
amount3
Daily cocaine
use amount4
Total income quartiel1
Number of suppliers2 (log10)
Unit price2 (log10) −.23
Cocaine subjective purity2
Cocaine expenses3 (log10) .71
Weekly purchases3 (log10) .38a .28b −.28b .47a
Purchase time3 (log10) .24b −.32a
Purchase amount3 (log10) .48a .32a .37a .28a
Daily cocaine use amount4 (log10) .32a .30a .34a .33a .43a .28b
Cocaine positive urine sample4 .21 .23 .33a −.29a −.21

Correlations in bold italics replicate similar significant relationships in prior studies with regular heroin users (Roddy and Greenwald, 2009; Roddy et al., 2011; Greenwald et al., 2013). Pearson correlation values of |r| ≤ .20 are suppressed for clarity. Correlations of |r| ≤ .23 that were significant at p < .05 without adjustment for multiple comparisons (ap < 0.01; bp < 0.05) were no longer significant using the Benjamini and Hochberg (1995) step-up procedure to control the false discovery rate (19 of 45 correlations declared significant; effective p ≤ .021).