Statistical Power Calculation
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Power (1 - β): Cohort Study
This utility can be used to calculate post-hoc satistical power gained with given sample size, when your objective is to test whether Relative Risk is significantly different than 1 in a Cohort Study. (In other words, your objective is to identify statistically significant risk factors.)
Formula used and other details
Sample Size Available in exposed group
Enter positive number more than 1
Required
Sample size available with you in exposed group.
Sample Size Available in non-exposed (control) group
Enter positive number more than 1
Required
Sample size available with you in non-exposed (control) group.
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.
One sided or two sided
Enter either 1 or 2
Required
One tailed or two tailed hypothesis
Select any two of these three
Relative Risk
Incidence Rate amongst exposed
Incidence Rate among non-exposed
Power (1 - β) =