lør, 07 03 2009 kl. 09:42 -0500, skrev James K. Lowden: > Alois Schlögl wrote: > > Skipping NA/NaN is valid for the mean as well as for any other > > statistical estimate. > > That is not always so. Suppose you intend to compute the mean of N values > but due to an error in your database query, 90% of those values are > missing. Are you prepared to say that the mean of the other 10% is > representative?
I would say that was the best estimate you could possibly get. > NaNs convey meaning, as Søren said. Actually, what I said was that there was a difference between something being not-a-number, and something being missing. It makes perfect sense to skip missing values when computing the mean value (in the statistical sense). However, it does not make sense to ignore NaN's when they convey the meaning that something went wrong somewhere else in your program. Jaroslav explained this well. Søren ------------------------------------------------------------------------------ Open Source Business Conference (OSBC), March 24-25, 2009, San Francisco, CA -OSBC tackles the biggest issue in open source: Open Sourcing the Enterprise -Strategies to boost innovation and cut costs with open source participation -Receive a $600 discount off the registration fee with the source code: SFAD http://p.sf.net/sfu/XcvMzF8H _______________________________________________ Octave-dev mailing list Octave-dev@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/octave-dev
