Sample Size Determination
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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
Your guesstimate of Mean in test arm (M1)
Required
Approxiate estimate of mean in test arm based on previous studies / pilot studies etc.
Your guesstimate of Standard Deviation of mean in test arm (SD1)
Required
Approxiate estimate of Standard Deviation of mean in test arm, based on previous studies / pilot studies etc.
Your guesstimate of mean in control arm (M2)
Required
Approxiate estimate of mean in control arm based on previous studies / pilot studies etc.
Your guesstimate of Standard Deviation of mean in control arm (SD2)
Required
Approxiate estimate of Standard Deviation of mean in control arm, based on previous studies / pilot studies etc.
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 to 99.99. Common values are 80 % and 90 %
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
Sample Size Required =