Re: One-Way Anova Repeated Measures: Main effect is significant, but post-hoc tests are not significant

Posted by David Marso on Jan 03, 2014; 3:35pm
URL: http://spssx-discussion.165.s1.nabble.com/One-Way-Anova-Repeated-Measures-Main-effect-is-significant-but-post-hoc-tests-are-not-significant-tp5723746p5723767.html

I have decided as a New Years resolution to swear off any further use of SPSS Macros.
In fact I am no longer going to use syntax at all.  
Henceforth, I'm going to do everything with the cute little pointy cliquey menu thingies!
I will also turn off my journaling to save disc space.
I will use OMS to save everything I could do with AGGREVATE.
My new TABLELOOK is going to be a reincarnated HotDog.

Bruce Weaver wrote

Ryan Black wrote

Sorry, but I can't resist plugging the MIXED procedure. :-)

I'm shocked!  What next?  Jon promoting the use of Python, perhaps?  :-O

Ryan Black wrote

JohnDoe,

Under certain conditions, it's perfectly acceptable to employ the Tukey HSD
procedure as a follow-up procedure in testing all-possible pairwise
comparisons in a repeated measures ANOVA. While it might take a little bit
of effort, this procedure can be employed in SPSS for your design.

But let's step back for a moment. What is your understanding of the
assumption of sphericity? How could a departure in sphericity affect the
the sampling distribution of the ratio of mean squares? Are you familiar
with the index, espilon? What is your estimate of epsilon?  What is your
understanding of the rule(s) of thumb regarding epsilon? What are the
corrections offered by SPSS?

I really appreciated Bruce's question/comment about the "...nature of the
repeated measures factor." It could have an impact not only on the post-hoc
tests performed but the model as well (e.g., general linear model versus
linear mixed model). For example, if your repeated measures variable is a
measure of time, it's possible to observe a decay in correlations between
residuals from observations more distant in time. This type of residual
correlation structure could be modeled in the MIXED procedure. Sorry, but I
can't resist plugging the MIXED procedure. :-)

Ryan


On Thu, Jan 2, 2014 at 12:13 PM, JohnDoe <[hidden email]> wrote:

> Thanks,
>
> As it was a repeated measures test, I was unable to select any post hocs
> except for LSD, Bonferroni, and Sidak. I have four levels in my design
>
>
>
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