Message-ID: <CAM_vjumDzATaUbgcBrN3uxvMP8v6vDABRv2Fh-vt9B8fH+S_vA@mail.gmail.com>
Date: 2012-05-04T14:07:24Z
From: Sarah Goslee
Subject: read-in, error???
In-Reply-To: <CA+e9w0DOeAHNysQzBsAY6eOpVwd3or7wTRVTD5CZTWi7KFAdgg@mail.gmail.com>
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