[Octave-bug-tracker] [bug #36646] [with patch] Stastic tests produce errors and warnings, when var(sample) == 0

[anonymous]

URL:
  <http://savannah.gnu.org/bugs/?36646>

                 Summary: [with patch] Stastic tests produce errors and
warnings, when var(sample) == 0
                 Project: GNU Octave
            Submitted by: None
            Submitted on: Mi 13 Jun 2012 13:02:50 UTC
                Category: None
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: None
                  Status: None
             Assigned to: None
         Originator Name: 
        Originator Email: 
             Open/Closed: Open
         Discussion Lock: Any
                 Release: 3.6.1
        Operating System: GNU/Linux

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Details:

All statistical tests I used behave unexpectedly when the variance of the one
or multiple input samples is 0. This sometimes leads to divide by zero
warning, but correct results, but sometimes (as in the case for anova) also
produces wrong results without warning, because of badly conditioned
subtraction that can lead to divide-by-small-negative-number instead of divide
by zero.

I have pinged this back and forth between different octave lists and was told
to report this here.

I have attached a patch for anova , and will attach two patches for t_test_2
and var_test tomorrow (they are on a different computer). The other tests have
to be fixed likewise.

Best,
Hannes



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File Attachments:


-------------------------------------------------------
Date: Mi 13 Jun 2012 13:02:50 UTC  Name: patch_anova.m  Size: 742B   By: None

<http://savannah.gnu.org/bugs/download.php?file_id=26013>

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