Sample Size Determination
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Clinical Trial: Equivalence Design
This utility can be used to calculate required sample size for a clinical trial with equivalence 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 %.
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).
Sample Size Required =