Re: Study about accuracy of statistical software, incl. Octave

[John W. Eaton]

On 24-Mar-2009, 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 floating-point. 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