Sample Size Determination
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Clinical Trial: Equivalence Design (Dichotomous outcome variable)
This utility can be used to calculate required sample size for a clinical trial with equivalence design and the outcome variable is dichotomous.
Formula used and other details
Your guesstimate of Proportion of desired outcome in test arm (P1)
Enter positive number between 0.01 to 99.99
Required
Approxiate estimate of Proportion of participants in test arm with desired outcome, based on previous studies / pilot studies etc. In percentage. (Between 0.01 to 99.99)
Your guesstimate of Proportion of desired outcome in control arm (P2).
Enter positive number between 0.01 to 99.99
Required
Approxiate estimate of Proportion of participants in control arm with desired outcome, based on previous studies / pilot studies etc. In percentage. (Between 0.01 to 99.99)
Ratio of Sample Size in two arms (Groups) (N2 / N1)
Enter number from 0.01 to 9.00
Required
Sample Size in Group 2 (control arm) / Sample Size in Group 1 (test arm)
Confidence Level %
Enter positive number between 0.01 to 99.99
Required
In percentage. Commonly used values are 95, 99 and 90. Should be between 0.01 to 99.99.
Power ( 1 - β)
Enter positive number between 0.01 and 99.99
Required
In Percentage. Should be between 0.01 and 99.99. Common values are 80 % and 90 %. Calculations are done considering two one sided tests (TOST).
Clinically Acceptable Margin for Equivalence (d)
Required
It is the clinically meaningful margin on either side of P2 to define equivalence of P1. Test arm proportion should be within control arm proportion by this equivalence margin to consider test intervention is equivalent to control intervention. In percentage. (Between 0.01 to 99.99)
Two sided test
Being an equivalence design, hypothesis test is always two sided. Calculations are done considering two one sided tests (TOST).
Sample Size Required =