I am trying to calculate sample size based on required effect size for my test (site found here: http://www.sample-size.net/sample-size-means/)
My inputs are as follows:
α (two-tailed) = .05
β = 0.100
Split of Test Vs. Control = .5
Desired Effect Size = .03
Standard deviation of the outcome in the population =
My confusion is in regards to this last step - is this the pooled Standard Deviation of my two groups? Not sure what to input here...any help would be appreciated!