[R] Increase Decimal Accuracy?

[Sundar Dorai-Raj]

Ann Hess wrote:
> Is there any way to increase the decimal accuracy for probability 
> distributions.  For example (in R):
> 
> 
>>1-pchisq(90,5)
> 
> [1] 0
> 
> But in Maple, I find that the value is 0.67193x10-17.
> 
> I need to compare some really small p-values...is there a way to increase 
> the decimal place accuracy beyond 1x10-16 (which seems to be the limit)?
> 
> Any help would be appreciated.
> 
> Ann
> 

Try

pchisq(90, 5, lower.tail = FALSE)

Also read FAQ 7.31.

http://cran.r-project.org/faqs.html

HTH,

--sundar