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. Author manuscript; available in PMC: 2009 Dec 1.
Published in final edited form as: Drug Alcohol Depend. 2008 Jul 31;98(3):249–263. doi: 10.1016/j.drugalcdep.2008.06.008

Table 2.

Mean Comparisons for External Marker Variables

Composite
Scales		 Total
Sample		 Female
(N=271)		 Male
(N=368)		 P-Value
Gender		 Miami
(N=186)		 St. Louis
(N=297)		 Sydney
(N=156)		 P-Value
Site
Criminal Index 2.99 1.39 3.80 <.001 2.88a 3.51a 1.39 <.001
CES-D 6.22 6.27d 6.05d NS 6.53a 6.47a 5.47 <.001
Motivation 15.99 15.91d 16.36d NS 16.72a 15.14 16.55a <.001
Stressful Life Events 1.57 1.58d 1.52d NS 1.61 1.65 1.38 NS
Support 4.01 4.10 3.93 .014 4.08 4.03 3.95 NS
Lifetime XTC Use 2.30 2.30d 2.36d NS 2.36a 2.18 2.44a <.001
# Days Used Past 30 Days 0.48 0.55d 0.51d NS 0.32a 0.34a 0.94 <.001
# Times/Days Past 30 Days 0.70 0.80d 0.79d NS 0.51a 0.43a 1.44 <.001
# Other Club Drugs Used¥ Past 12 mos. 0.27 0.29 0.44 .006 0.44a 0.24 0.42a <.001
# of Other Drugs Used (no club drugs) Past 12 mos. 3.93 3.68 4.00 .017 3.95a 4.07a 3.52 .003
# of Other Drugs Used (no XTC) 4.28 3.98 4.44 .004 4.39a 4.30a 3.94 NS

Note. XTC = Ecstasy. Least square (adjusted) means are reported for subgroup comparisons.

a–c

Mean comparisons by site.

d

Mean comparisons by gender. P-Values for Site comparisons are based on Ftest statistics. P-Values for Gender comparisons are based on Student’s t-test. Means in the same row that do not share superscripts differ significantly in Scheffe post hoc analysis. In some cases, overall F-test may not be significant and post hoc comparisons are presented for purposes of clarity. NS = not significant.