[R] Power sampling

[Uwe Ligges]

Thomas Schönhoff wrote:

> Hello,
> 
> after a unsuccessful search in lists maliarchive I wonder how I could 
> estimate the power of a sample size related to an unknown population.
> 
> Given the following (fake))situation:
> 
> I do have a database containing about 5 millions observations over 70 
> variables.
> I would like to compute (as epidemiologists are used to) the required 
>  size of a sample to do some test on a test sample (test data), later 
> doing some subsequent analysis of a new sample to build a prediction model.
> 
> Help facilities of R show some entries regarding power, but none of them 
> seemed to be appropriate for my purpose (maybe I am wrong, but sometimes 
> I have some difficulties to decipher the message of those tiny hints for 
> available packages)

You have to tell us for which test you are going to calculate the power 
... (and there might be nothing, since calculating the power precisely 
is not always that easy).

Uwe Ligges



> I would appreciate somebody effort to point me to the right 
> package/function to archieve this task!
> 
> 
> regards
> 
> Thomas
> 
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