Statistical Power Calculation
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Power in Clinical Trial: Superiority Design
This utility can be used to calculate statistical power with given sample size for a clinical trial with superiority 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.
Superiority Margin (d)
Required
It is the limit beyond control arm mean, which is used to define superiority of the test arm mean. Can be positive or negative depending on the direction of Supriority.
Superiority limit is positive, if superiority of test arm is defined when test arm mean is more than control arm mean. In rare situations, superiority of test arm is defined when test arm mean is less than control arm mean. In such rare situations superiority limit is negative.
One sided test
Being a superiority design, hypothesis test is always one sided
Power ( 1 - β) =