Statistical Power Calculation
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Power of Clinical Trial: Non-inferiority Design
This utility can be used to calculate required sample size for a clinical trial with non-inferiority design when the outcome variable is in ratio scale.
Formula used and other details
Mean in test arm (M1).
Required
Mean in test arm in your study(M1).
Standard Deviation of mean in test arm (SD1)
Required
Standard Deviation of mean in test arm (SD1)
Sample Size in test arm(N1)
Enter positive number between 0 to 1000000
Required
Total number of participants in test arm (N1).
Mean in control arm (M2)
Required
Mean in control arm (M2).
Standard Deviation of mean in control arm (SD2)
Required
Standard Deviation of mean in control arm
Sample Size in control arm(N2)
Enter positive number between 0 to 1000000
Required
Total number of participants in test arm (N1).
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.
Non-Inferiority Margin (d)
Required
It is the difference between control arm mean and test arm mean which can be tolerated to define non-inferiority. Can be positive or negative depending on the direction of non-inferiority.
It is positive where inferiorty of test arm is defined, if test arm mean is less than control arm mean. In rare situaions, non-inferiority limit is negative, where inferiority of test arm is defined when test arm mean is more than control arm mean.
One sided test
Being a non-inferiority design, hypothesis test is always one sided
Power ( 1 - β) =