From ligges at statistik.uni-dortmund.de  Fri Sep 24 17:12:17 2004
From: ligges at statistik.uni-dortmund.de (ligges@statistik.uni-dortmund.de)
Date: Fri Sep 24 17:12:19 2004
Subject: [Rd] bug in  power.t.test( ) (PR#7245)
Message-ID: <20040924151217.1D5A610FD1@slim.kubism.ku.dk>

Martin Maechler wrote:

>>>>>>"UweL" == Uwe Ligges <ligges@statistik.uni-dortmund.de>
>>>>>>    on Fri, 24 Sep 2004 08:43:56 +0200 (CEST) writes:
> 
> 
>     UweL> mai@ms.uky.edu wrote:
>     >> Full_Name: Mai Zhou Version: 1.9.1 OS: Win XP
>     >> Professional Submission from: (NULL) (12.222.227.93)
>     >> 
>     >> 
>     >> 
>     >>> power.t.test(n=25, delta=0.1, sig.level=1.1,
>     >>> strict=TRUE, type="one.sample")
>     >> 
>     >> 
>     >> One-sample t test power calculation
>     >> 
>     >> n = 25 delta = 0.1 sd = 1 sig.level = 1.1 power =
>     >> 1.088311 alternative = two.sided
>     >> 
>     >> ### power can never be over one!  Of course, sig.level
>     >> should not take value > 1 ### either.  ### Possible
>     >> solution: A check in the input to truncate sig.level into
>     >> [0, 1]??
> 
>     UweL> Well, an error (or at least warning) message seems to
>     UweL> be more appropriate rather than silently changing some
>     UweL> values, e.g. somehwere at the top of the functions
>     UweL> body:
> 
>     UweL>      if(any(sig.level < 0 | sig.level > 1))
>     UweL>               stop("sig.level must be in [0,1]")
> 
> yes, in principle;
> thank you, Uwe!
> 
> Since  sig.level can also be NULL

Yes.

> (which works with the way you
> constructed the test - on purpose?), I'd use the test a bit
> differently.
> 
> BTW, did you know that e.g., sig.level or delta can be *vectors*

Yes, hence the "|" rather than "||".

Uwe


> giving vectorized results - at least in some cases...
> That will hopefully leed to more documentation / code updates, 
> but not for 2.0.0 I presume.
> 
> Martin Maechler


[Rd] bug in power.t.test( ) (PR#7245)
ligges@statistik.uni-dortmund.de