Date:         Tue, 29 Jan 2008 06:15:36 -0500
Reply-To:     Shin <shintaro.okazaki@UAM.ES>
Sender:       "SPSSX(r) Discussion" <SPSSX-L@LISTSERV.UGA.EDU>
From:         Shin <shintaro.okazaki@UAM.ES>
Subject:      Bonferroni-adjusted t-tests

Dear all:

I have a question regarding t-tests. One of the reviewers suggested me to
perform "Bonferroni-adjusted t-tests". I understand that Bonferroni is one
of the post hoc methods in MULTIPLE group comparisons of ANOVA. However,
our study deals with only TWO groups.

His/her main argument is that our results of two-group comparison
generated very small means, but probably due to a relatively large sample
size (n1=870, n2=780), t-tests detected statistical significance at 0.05,
which may not have any practical meaning. Therefore, he/she suggested us
to "adjuste the alpha level." He/She implies that if I indeed adjust the
alpha, some of the comparisons may not result in statistical significance.

Could anybody explain how we could perform Bonferroni-adjusted t-tests IN
A TWO-GROUP COMPARISON via SPSS? I have looked at the main menu but could
not find any option of this kind, except in ANOVA as a post hoc option.
Thank you for your help in advance.

Shin

S. Okazaki
Autonomous University of Madrid

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