[R] Power curves

[Chuck Cleland]

On 4/14/2008 6:21 AM, Louisa Hay wrote:
>  
> Hi,
> I am trying to create a power curve to show how the power of a t-test varies depending on the mean. Any ideas how I should go about this?
> Louisa

   Something like this maybe?

mydiffs <- seq(.05,1,.05)

mypower <- vector("numeric", 20)

for(i in 1:20){
   mypower[i] <- power.t.test(n=100, sd=1, delta=mydiffs[i])$power
}

plot(mymeans, mypower, xlab="delta", ylab="Power", type="b")

   See ?power.t.test

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Chuck Cleland, Ph.D.
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