Re: [R] delta and sd parameters for power.t.test [solved]

2017-12-15 Thread Lasse Kliemann
Lasse Kliemann writes: > What is the rationale behind having both the delta and sd parameters for > the power.t.test function? For the relevant noncentrality parameter, we > only need the ratio delta/sd. If my effect size is given as Cohen's d, > then I only got that ratio and not sd. > > As far

Re: [R] delta and sd parameters for power.t.test

2017-12-14 Thread David Winsemius
> On Dec 14, 2017, at 2:26 PM, Lasse Kliemann wrote: > > What is the rationale behind having both the delta and sd parameters for > the power.t.test function? One is the standard deviation of the hypothesized data (or pooled sd in the case of two sample) under the "alternative" and one is the

[R] delta and sd parameters for power.t.test

2017-12-14 Thread Lasse Kliemann
What is the rationale behind having both the delta and sd parameters for the power.t.test function? For the relevant noncentrality parameter, we only need the ratio delta/sd. If my effect size is given as Cohen's d, then I only got that ratio and not sd. As far as I see, in such a case, I can spec