On 3/12/2006 6:39 PM, [EMAIL PROTECTED] wrote: > Full_Name: Matthew Davis > Version: 2.2.0 > OS: OS X (10.4.5) > Submission from: (NULL) (209.107.120.195) > > > the mean of my sample x is 0.2, and when I check mean(x)<=0.2 I get a TRUE > value, when I check mean(x)<=(1-0.8) I get a FALSE value. (x <- c(0, 1, 0, 0, > 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0))
Why make this so complicated? The natural conclusion from that is that 0.2 is not equal to (1-0.8), and indeed: > (1-0.8) == 0.2 [1] FALSE The problem is that neither 0.2 nor 0.8 can be represented exactly, so when you do calculations using them you are doing approximations. The approximation involving your mean is different than the one involving (1-0.8). This is an FAQ, 7.31 Why doesn't R think these numbers are equal? This is not a bug. Duncan Murdoch ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
