read-in, error???
Hi Istvan, That's most unusual, and quite unlikely (and much larger than the usual floating-point rounding errors). Please provide a reproducible example. I assume you got the data from here: http://www.itl.nist.gov/div898/strd/anova/SmLs07.dat What did you do with it then? How did you delete the header rows? What R code did you use to read it in? What OS and version of R are you working with? R has been well-validated; it's more likely that you did something sub-optimal while importing the data. Sarah
On Fri, May 4, 2012 at 9:54 AM, Istvan Nemeth <furgeurge at gmail.com> wrote:
Dear Users! I encountered with some problem in data reading while I challenged R (and me too) in a validation point of view. In this issue, I tried to utilize some reference datasets ( http://www.itl.nist.gov/div898/strd/index.html). And the result departed a bit from my expectations. This dataset dedicated to challenge cancellation and accumulation errors (case SmLs07), that's why this uncommon look of txt file. Treatment ? Response ? ? ? ? ? 1 ? ?1000000000000.4 ? ? ? ? ? 1 ? ?1000000000000.3 ? ? ? ? ? 1 ? ?1000000000000.5 ? ? ? ? ? ...... ? ? ? ? ? 2 ? ?1000000000000.2 ? ? ? ? ? 2 ? ?1000000000000.4 ? ? ? ? ? ..... ? ? ? ? ? 3 ? ?1000000000000.4 ? ? ? ? ? 3 ? ?1000000000000.6 ? ? ? ? ? 3 ? ?1000000000000.4 ? ? ? ? ? ......... then after a read.table() I expect the same set instead I've got this: ? ?Treatment ? ? ? ? ? ? ?Response 1 ? ? ? ? ? 1 1000000000000.4000244 2 ? ? ? ? ? 1 1000000000000.3000488 3 ? ? ? ? ? 1 1000000000000.5000000 ......... 22 ? ? ? ? ?2 1000000000000.3000488 23 ? ? ? ? ?2 1000000000000.1999512 24 ? ? ? ? ?2 1000000000000.4000244 ....... 58 ? ? ? ? ?3 1000000000000.4000244 59 ? ? ? ? ?3 1000000000000.5999756 60 ? ? ? ? ?3 1000000000000.4000244 61 ? ? ? ? ?3 1000000000000.5999756 62 ? ? ? ? ?3 1000000000000.4000244 ...... a lots of number from the space. I assume that these numbers come from the binary representation of such a tricky decimal numbers but my question is how can I avoid this feature of the binary representation? Moreover, I wondered that it may raise some question in a regulated environment.
Sarah Goslee http://www.functionaldiversity.org