Sample Size Determination
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Clinical Trial: Superiority Design (Dichotomous outcome variable)
This utility can be used to calculate required sample size for a clinical trial with superiority 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). Should be less than P1.
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 integer 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 to 99.99. Common values are 80 % and 90 %
Superiority margin (d)
Required
It is the clinically significant margin to define superiority. Test arm proportion should be more than control arm proportion by this superiority margin to consider test intervention is superior to control intervention. It should be less than the actual absolute dfference between proportions in two arms. In percentage. (Between 0.01 to 99.99)
One sided test
Being a superiority design, hypothesis test is always one sided
Sample Size Required =