Sample Size Determination
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Hypothesis test for Relative Risk.
This utility can be used to calculate required 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
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 %
Control (non-exposed): Cohort (exposed) Ratio
Enter number integer from 0.01 to 9.00
Required
Ratio of Participants in Cohort Group to Control (non-exposed) Group
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
Sample Size Required =
Sample Size by Other methods =