Finding 'ncp' for t

(Ted Harding) <Ted.Harding at nessie.mcc.ac.uk> writes:

Hi Folks,

I'm looking for a neat procedure for the following:

Given t0 such that

  pt(t0,df,ncp=0) = alpha (given)

find ncp0 such that for given beta

  pt(t0,df,ncp=ncp0) = (1 - beta)

(In other words, what's the ncp such that you get power (1-beta)
to detect it, using a 1-sided test with size alpha when ncp = 0?)

In the past I've done the groping by hand, but this time it
needs to be done many times over, so a good solver for ncp0
in this situation would be handy.

You might want to peek inside power.t.test(). Or just use it...