Perhaps this is related to PR#1228

http://r-bugs.biostat.ku.dk/cgi-bin/R/Accuracy?id=1228;user=guest

which seems to have been improved in recent versions.

Andreas Pauling <[EMAIL PROTECTED]> 3/29/2004 9:01:40 AM >>>

Dear R people


I came across a strange thing:


sd(rep(0.01, 15)) #0 sd(rep(0.001, 15)) #4.489023e-19 sd(rep(0.00001, 15)) #0 sd(rep(0.00000001,15)) #1.712427e-24

sd(rep(0.01,      13))  #1.805557e-18
sd(rep(0.001,     13))  #4.513894e-19
sd(rep(0.00001,   13))  #0
sd(rep(0.00000001,13))  #0

sd(rep(5.01,      15))  #0
sd(rep(5.001,     15))  #4.489023e-19
sd(rep(5.00001,   15))  #1.838704e-15
sd(rep(5.00000001,15))  #9.19352e-16

sd(rep(5.01,      13))  #9.244454e-16
sd(rep(5.001,     13))  #9.244454e-16
sd(rep(5.00001,   13))  #1.848891e-15
sd(rep(5.00000001,13))  #0

Why gives sd sometimes zero and sometimes values close to zero
and why does it depend on the value and on how many times it is
repeated?
Shouldn't it give always zero?
Is there a way to control this?
...

-- Chuck Cleland, Ph.D. NDRI, Inc. 71 West 23rd Street, 8th floor New York, NY 10010 tel: (212) 845-4495 (Tu, Th) tel: (732) 452-1424 (M, W, F) fax: (917) 438-0894

______________________________________________
[EMAIL PROTECTED] mailing list
https://www.stat.math.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html

Reply via email to