[R] Power curves

[Chuck Cleland]

On 4/14/2008 6:35 AM, Chuck Cleland wrote:
> 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")

   Sorry - that last line should be:

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

>    See ?power.t.test
> 
>> _________________________________________________________________
>>
>>
>> 	[[alternative HTML version deleted]]
>>
>> ______________________________________________
>> R-help at r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.  

-- 
Chuck Cleland, Ph.D.
NDRI, Inc. (www.ndri.org)
71 West 23rd Street, 8th floor
New York, NY 10010
tel: (212) 845-4495 (Tu, Th)
tel: (732) 512-0171 (M, W, F)
fax: (917) 438-0894