[R] p-values

Spencer Graves spencer.graves at pdf.com
Sun Aug 7 04:34:59 CEST 2005


Hi, Peter:

	  Please see my reply of a few minutes ago subject:  exact 
goodness-of-fit test.  I don't know Rayner and Best, but the same 
method, I think, should apply.  spencer graves

Peter Ho wrote:

> HI R-users,
> 
> I am trying to repeat an example from Rayner and Best "A contingency 
> table approach to nonparametric testing (Chapter 7, Ice cream example).
> 
> In their book they calculate Durbin's statistic, D1, a dispersion 
> statistics, D2, and a residual. P-values for each statistic is 
> calculated from a chi-square distribution and also Monte Carlo p-values.
> 
> I have found similar p-values based on the chi-square distribution by 
> using:
> 
>  > pchisq(12, df= 6, lower.tail=F)
> [1] 0.0619688
>  > pchisq(5.1, df= 6, lower.tail=F)
> [1] 0.5310529
> 
> Is there a way to calculate the equivalent Monte Carlo p-values?
> 
> The values were 0.02 and 0.138 respectively.
> 
> The use of the approximate chi-square probabilities for Durbin's test 
> are considered not good enough according to Van der Laan (The American 
> Statistician 1988,42,165-166).
> 
> 
> Peter
> --------------------------------
> ESTG-IPVC
> 
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-- 
Spencer Graves, PhD
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