Statistical Power Calculation
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Power: Clinical Trial: Equivalence Design
This utility can be used to calculate statistical power gained with given sample size for a clinical trial with equivalence 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.
Clinically Acceptable Equivalence Margin (d)
Required
It is the clinically meaningful margin on either side of P2 to define equivalence of P1. Test arm mean should be within control arm mean by this equivalence margin to consider test intervention is equivalent to control intervention.
Two sided test
Being an equivalence design, hypothesis test is always two sided. However sample size is calculated using two one sided tests (TOST).
Power ( 1 - β) =