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Field
Power calculation: Minimum Detectable Effect Size for Main Outcomes
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Before
Power calculations are based on 80% power and a 0.05 Type 1 error probability. Our preferred ICC is 0.06, based on a mid-point of the ICCs for drug use among adolescents documented in Resnicow et a (2010). Our estimates support that the study is well-powered to detect effects of between 5% to 13% improvements in various beliefs, a 4.3pp increase in placement rates, a 4.4pp reduction in dropouts, a 4.2pp increase in attendance, and a 1.9pp reduction in drug use.
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After
Power calculations are based on 80% power and a 0.05 Type 1 error probability. Our preferred ICC is 0.06, based on a mid-point of the ICCs for drug use among adolescents documented in Resnicow et a (2010). Our estimates support that the study is well-powered to detect effects of between 4% to 12% improvements in various beliefs, a 3.7pp increase in placement rates, a 3.8pp reduction in dropouts, a 3.7pp increase in attendance, and a 1.7pp reduction in drug use.
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