[R] Power graph for two Proportion

[Jim Lemon]

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