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Subject: bug fix: Bonferroni corrected p-values
Date: Tue, 09 Oct 2001 18:50:06 -0400
From: "Thomas E. Nichols" <>

Hi all,

In June new functions were released to incorporate Bonferroni
results.  These functions (silently) gave SPM corrected thresholds and
p-values based the minimum of Bonferroni and Random Field results.
(Both methods are valid, though conservative to differing degrees;
hence it's OK to take the minimum of each).

Due to a bug/typo, spm_P.m wasn't using Bonferroni-corrected p-values
even if they were smaller.  Corrected thresholds are OK, but
corrected p-values did not take advantage of the Bonferroni p-values.

The only impact of this bug was that the corrected p-values in
the tabular output are not as small as they can be:  When the Bonferroni
corrected p-value is smaller they still used the random field p-value.

**If** you picked up the new functions in June, please grab this fix at

Sorry for any inconvenience.

See this message on the Bonferroni updates:


    -- Thomas Nichols --------------------   Department of Biostatistics     University of Michigan                     1420 Washington Heights
    --------------------------------------   Ann Arbor, MI 48109-2029