The t-distribution functions recognize that df=Inf is equivalent to the standard normal distribution:
> pt(1,df=Inf) [1] 0.8413447 > pnorm(1) [1] 0.8413447
On the other hand, pf() will accept Inf for df1, but returns the wrong result:
> pf(1,df1=Inf,df2=1) [1] 1
whereas the correct limiting value is
> pchisq(1,df=1,lower.tail=FALSE) [1] 0.3173105
pf() returns NaN when df2=Inf:
> pf(1,df1=1,df2=Inf) [1] NaN Warning message: NaNs produced in: pf(q, df1, df2, lower.tail, log.p)
although the correct value is available as
> pchisq(1,df=1) [1] 0.6826895
Gordon
> version
_
platform i386-pc-mingw32
arch i386
os mingw32
system i386, mingw32
status
major 2
minor 1.0
year 2005
month 04
day 18
language R
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Dr Gordon K Smyth, Senior Research Scientist, Bioinformatics,
Walter and Eliza Hall Institute of Medical Research,
1G Royal Parade, Parkville, Vic 3050, Australia
Tel: (03) 9345 2326, Fax (03) 9347 0852,
Email: [EMAIL PROTECTED], www: http://www.statsci.org______________________________________________ R-devel@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
