[R] Power graph for two Proportion
Jim Lemon
jim at bitwrit.com.au
Tue Jun 17 23:59:22 CEST 2014
On Tue, 17 Jun 2014 10:30:17 AM suganthiny cumarasamy wrote:
> Dear R mailing listers,
>
> I am try to find the different power calculation for
> p1=0.2 and p2=0.4 , with significant level=0.05 (one sided test)
> I would like to have a graph y -axis as a power and
> x-axis as a sample size .
>
> I run this command for different value of power. and get the n and
power
> pwr.2p.test(h=ES.h(0.4,0.2), power = 0.87,
> sig.level=0.05,alternative="greater")
>
> Is there is any easy way i can do power graph using the two proportion
in
> R.
>
Hi Suga,
I'm not familiar with pwr.2p.test, but if it takes a vector of power values,
you could do something like this:
# get a vector of sample sizes for different values of power
# it probably won't be this straightforward
powers<-seq(0.5,0.95,by=0.05)
sample_sizes<-pwr.2p.test(h=ES.h(0.4,0.2),power=powers,
sig.level=0.05,alternative="greater")
plot(sample_sizes,powers)
Jim
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