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Re: Study about accuracy of statistical software, incl. Octave
From: 
John W. Eaton 
Subject: 
Re: Study about accuracy of statistical software, incl. Octave 
Date: 
Tue, 24 Mar 2009 14:50:09 0400 
On 24Mar2009, Marco Caliari wrote:
 > What do you mean by "exact mean" here? I don't think any of the three
 > numbers are exactly representable in IEEE floatingpoint. It would be
 > better to choose numbers that have an exact representation, such as
 > 1e7 + 0.25, 1e7 + 0.5, 1.7 + 0.75 or such. Otherwise, you can't avoid
 > introducing errors just by writing these numbers.

 I agree with you, Jaroslav. On the other hand, in the paper it is
 written that R can compute the standard deviation with 15 correct digits.
 Actually, Octave can compute the mean with 14 correct digits and with 15
 correct digits with the patch I sent. The standard deviation with 8
 correct digits.
Since R is free software, we should be able to do just as well. Have
you looked at precisely what it does?
jwe
 Re: Study about accuracy of statistical software, incl. Octave, (continued)
 Re: Study about accuracy of statistical software, incl. Octave, Jaroslav Hajek, 2009/03/22
 Study about accuracy of statistical software, incl. Octave, John W. Eaton, 2009/03/24
 Re: Study about accuracy of statistical software, incl. Octave, Marco Caliari, 2009/03/24
 Re: Study about accuracy of statistical software, incl. Octave, Jason Riedy, 2009/03/24
 Re: Study about accuracy of statistical software, incl. Octave, Marco Caliari, 2009/03/24
 Re: Study about accuracy of statistical software, incl. Octave, Jaroslav Hajek, 2009/03/24
 Re: Study about accuracy of statistical software, incl. Octave, Marco Caliari, 2009/03/24
 Re: Study about accuracy of statistical software, incl. Octave,
John W. Eaton <=
 Re: Study about accuracy of statistical software, incl. Octave, Marco Caliari, 2009/03/25
 Re: Study about accuracy of statistical software, incl. Octave, Jaroslav Hajek, 2009/03/24
 Re: Study about accuracy of statistical software, incl. Octave, David Thompson, 2009/03/24
 Re: Study about accuracy of statistical software, incl. Octave, Jason Riedy, 2009/03/24
 Re: Study about accuracy of statistical software, incl. Octave, Jaroslav Hajek, 2009/03/24
 Re: Study about accuracy of statistical software, incl. Octave, Marco Caliari, 2009/03/25