[R] Variance for Vector of Constants is STILL Not Zero

[Barry Zajdlik]

Hello all,

Thanks for the responses but I am still annoyed by this seemingly simple
problem; I recorded sessionInfo() as below.

x<-rep(0.02,10)
> var(x)
[1] 1.337451e-35
>  sessionInfo()
R version 2.1.0, 2005-04-18, i386-pc-mingw32 

attached base packages:
[1] "methods"   "stats"     "graphics"  "grDevices" "utils"
"datasets" 
[7] "base"     
>


I then decided to download the latest version today but obtained the
same result.

> x<-rep(0.02,10)
> var(x)
[1] 1.337451e-35

> sessionInfo()
R version 2.2.1, 2005-12-20, i386-pc-mingw32 

attached base packages:
[1] "methods"   "stats"     "graphics"  "grDevices" "utils"
"datasets" 
[7] "base"    


I Changed .Machine$double.eps to make the calculations LESS accurate.
My thought was that if I reduced the precision, 1-eps would return 1
instead of some number less than 1.  My thought was that if eps were
sufficiently large my sample problem would return a zero.  This didn't
happen though.

Again, any thoughts would be appreciated.

Regards,
Barry Zajdlik