jonathan-cran@swintons.net
2003-Dec-18 13:54 UTC
[Rd] qbinom when probability is 1 (PR#5900)
Full_Name: Jonathan Swinton Version: 1.8.0 OS: Windows 2000 Submission from: (NULL) (193.132.159.34) Calling qbinom with a sample probability of 1 returns NaN> qbinom(p=0.95,size=10,prob=1)[1] NaN I believe that this is wrong and that qbinom(p,size,prob=1) should always be size for 0<p<=1. The documentation says that The quantile is defined as the smallest value x such that F(x) > p, where F is the distribution function. Version: platform = i386-pc-mingw32 arch = i386 os = mingw32 system = i386, mingw32 status = major = 1 minor = 8.0 year = 2003 month = 10 day = 08 language = R Windows 2000 Professional (build 2195) Service Pack 3.0 Search Path: .GlobalEnv, package:lattice, package:Hmisc, package:XML, package:graph, package:methods, package:ctest, package:mva, package:modreg, package:nls, package:ts, Autoloads, package:base
The cases of prob=0 and prob=1 were specifically excluded in the code, as well as n=0. I've added special-case code for all of these. On Thu, 18 Dec 2003 jonathan-cran@swintons.net wrote:> Full_Name: Jonathan Swinton > Version: 1.8.0 > OS: Windows 2000 > Submission from: (NULL) (193.132.159.34) > > > Calling qbinom with a sample probability of 1 returns NaN > > qbinom(p=0.95,size=10,prob=1) > [1] NaN > > I believe that this is wrong and that qbinom(p,size,prob=1) should always be > size for 0<p<=1. > > The documentation says that > > The quantile is defined as the smallest value x such that F(x) >> p, where F is the distribution function. > > > > Version: > platform = i386-pc-mingw32 > arch = i386 > os = mingw32 > system = i386, mingw32 > status = > major = 1 > minor = 8.0 > year = 2003 > month = 10 > day = 08 > language = R > > Windows 2000 Professional (build 2195) Service Pack 3.0 > > Search Path: > .GlobalEnv, package:lattice, package:Hmisc, package:XML, package:graph, > package:methods, package:ctest, package:mva, package:modreg, package:nls, > package:ts, Autoloads, package:base > > ______________________________________________ > R-devel@stat.math.ethz.ch mailing list > https://www.stat.math.ethz.ch/mailman/listinfo/r-devel > >-- Brian D. Ripley, ripley@stats.ox.ac.uk Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595