FAQ 7.31 ir. Thierry Onkelinx Instituut voor natuur- en bosonderzoek / Research Institute for Nature and Forest team Biometrie & Kwaliteitszorg / team Biometrics & Quality Assurance Kliniekstraat 25 1070 Anderlecht Belgium
To call in the statistician after the experiment is done may be no more than asking him to perform a post-mortem examination: he may be able to say what the experiment died of. ~ Sir Ronald Aylmer Fisher The plural of anecdote is not data. ~ Roger Brinner The combination of some data and an aching desire for an answer does not ensure that a reasonable answer can be extracted from a given body of data. ~ John Tukey 2016-04-05 13:34 GMT+02:00 Rainer Johannes <johannes.rai...@eurac.edu>: > Dear All, > > I have the following problem: > > I have a function in which I check if the difference between values is > smaller or equal to a certain threshold. I however realized that I might > get there some unexpected results: > > > abs(1 - 0.95) >= 0.05 > [1] TRUE > ## So that’s fine, but: > > abs(1 - 0.95) <= 0.05 > [1] FALSE > > Apparently, abs(1 - 0.95) is not equal to 0.05, which I find however quite > disturbing. > > Along these lines: > > abs(0.95 - 1) > 0.05 > [1] TRUE > > abs(0.95 - 1) < 0.05 > [1] FALSE > > I guess that has to do with the floating point representation of the data? > > Is there something I miss or is there any solution to this? > Thanks for any help! > > cheers, jo > > > > I tried this on different R-version (including 3.2.3 and 3.3.0 alpha); The > R-version I used for the code above is: > > > sessionInfo() > R version 3.0.2 (2013-09-25) > Platform: x86_64-unknown-linux-gnu (64-bit) > > locale: > [1] LC_CTYPE=en_US.UTF-8 LC_NUMERIC=C > [3] LC_TIME=en_US.UTF-8 LC_COLLATE=en_US.UTF-8 > [5] LC_MONETARY=en_US.UTF-8 LC_MESSAGES=en_US.UTF-8 > [7] LC_PAPER=en_US.UTF-8 LC_NAME=C > [9] LC_ADDRESS=C LC_TELEPHONE=C > [11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C > > attached base packages: > [1] stats graphics grDevices utils datasets methods base > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
