Minimum detectable effect size for main outcomes (accounting for sample
design and clustering)
We have two primary outcomes: quizzes and midterm exams.
For 600 students taking 6 quizzes, assuming 80% power at a 5% significance level (two-sided) the minimal detectable effect size is 0.093 SD, where SD is the within-student standard deviation of quiz scores.
Assuming 600 completed midterm exams, the minimal detectable effect per additional exposure (going from 0 to 1, 1 to 2, etc., assuming the effect is linear) for 80% power, two-sided test, α=0.05, is 0.132 SD of the residualized exam score.
Power for quizzes: For 600 students taking 6 quizzes, assuming 80% power at a 5% significance level (two-sided) the minimal detectable effect is 0.093 SD, where SD is the within-student standard deviation of quiz scores.
Power for midterm exams: Assuming 600 completed midterm exams, the minimal detectable effect per additional exposure (going from 0 to 1, 1 to 2, etc., assuming the effect is linear) for 80% power, two-sided test, α=0.05, 600 students, no controls, is 0.132 SD of the residualized exam score.