[R] function for the average or expected range?; CORECTION

[Spencer Graves]

Hi, Greg: 

      Thanks very much for the reply. 

      1.  The 'ptukey' and 'qtukey' function are the distribution of the 
studentized range, not the range.  I tried "sum(ptukey(x, 2, df=Inf, 
lower=FALSE))*.1" and got 1.179 vs. 1.128 in the standard table of d2 
for n = 2 observations per subgroup. 

      2.  I tried simulation and found that I needed 1e7 or 1e8 random 
normal deviates to get the accuracy of the published table. 

      3.  Then I programmed in Excel the integral over seq(-5, 5, .1) 
using a correction to the formula I got from Kendall and Stuart and got 
the exact numbers in the published table except in one case where it was 
off by 1 in the last significant digit. 

      Thanks again,
      Spencer

Greg Snow wrote:
> The "ptukey" and "qtukey" functions may be what you want (or at least in
> the right direction).
>
> You could also easily estimate this by simulation.
>
> Hope this helps,
>
>