Posted by
Mike on
Jan 11, 2011; 2:23pm
URL: http://spssx-discussion.165.s1.nabble.com/Three-Way-Anova-Post-Hoc-Comparisons-tp3336188p3336523.html
Just a couple of comments:
(1) This type of analysis appears to straddle the fence between
planned comparisons and post hoc multiple comparisons. For
main effects, the distinction is not important but for the intereactions,
they become relevant because of (a) Type I error concerns and
(b) level of statistical power.
(2) An ordinary ANOVA would produce 7 potentially significant
effects (3 main effects and 4 interactions). One could argue that
one can ignore the "family-wise Type I" error rate (which would
be calculated by
Overall alpha = (1 - (1-alpha per comparison)**7)
Assuming a per comparisons/F test result is judged with a traditional
per comparison alpha of .05, after evaluating the seven results, the
overall Type I error rate is .30, that is, there is a 30% chance that
one of the results is statistically significant. If one did all of the
tests below, because there are 13 comparisons, the overall
alpha would be .49. NOTE: since unadjusted or Lease Significant
Difference (LSD) tests are being conducted and if the independent
variables have more than 2 levels, there will be additional tests.
It would appear that after all statistical tests are done, the overall
probability of having made a Type I error would be around .50
or greater.
(3) The main effects have more statistical power than the interactions
and the lower order
----- Original Message -----
From: "Ginkel, Joost van" <
[hidden email]>
To: <
[hidden email]>
Sent: Tuesday, January 11, 2011 5:33 AM
Subject: Re: Three-Way Anova Post Hoc Comparisons
> Try this (only available through syntax):
>
> UNIANOVA Y BY A B C
> /METHOD=SSTYPE(3)
> /INTERCEPT=INCLUDE
> /EMMEANS=TABLES(A) COMPARE ADJ(LSD)
> /EMMEANS=TABLES(B) COMPARE ADJ(LSD)
> /EMMEANS=TABLES(C) COMPARE ADJ(LSD)
> /EMMEANS=TABLES(A*B) COMPARE (A) ADJ(LSD)
> /EMMEANS=TABLES(A*B) COMPARE (B) ADJ(LSD)
> /EMMEANS=TABLES(A*C) COMPARE (A) ADJ(LSD)
> /EMMEANS=TABLES(A*C) COMPARE (C) ADJ(LSD)
> /EMMEANS=TABLES(B*C) COMPARE (B) ADJ(LSD)
> /EMMEANS=TABLES(B*C) COMPARE (C) ADJ(LSD)
> /EMMEANS=TABLES(A*B*C) COMPARE (A) ADJ(LSD)
> /EMMEANS=TABLES(A*B*C) COMPARE (B) ADJ(LSD)
> /EMMEANS=TABLES(A*B*C) COMPARE (C) ADJ(LSD)
> /CRITERIA=ALPHA(.05)
> /DESIGN=A B C A*B A*C B*C A*B*C.
>
> Good luck!
>
> Best Regards,
>
> Joost van Ginkel
>
> Joost R. van Ginkel, PhD
> Leiden University
> Faculty of Social and Behavioural Sciences
> PO Box 9555
> 2300 RB Leiden
> The Netherlands
> Tel: +31-(0)71-527 3620
> Fax: +31-(0)71-527 3945
>
>
> -----Original Message-----
> From: SPSSX(r) Discussion [mailto:
[hidden email]] On Behalf Of
> komakino0
> Sent: Tuesday, January 11, 2011 11:19 AM
> To:
[hidden email]
> Subject: Three-Way Anova Post Hoc Comparisons
>
> In my data I have three independent variables; intervention
> (intervention vs control group), gender (male vs female) and country
> (country1, country2, country3). I have a three way interaction and I
> don't know how to conduct post hoc analyses. Basicly first I have to
> create a intervention-control difference. Then, I have to do this for
> gender specific. Afterwards I have to create a country specific
> difference for each gender specific intervention-control difference.
> The most advanced post hoc comparison I have seen is 2- way mixed design
> until now. SO I don't know what to do with this 3-way post-hoc. I
> appreciate even a tiny bit of help:) Thank you very much.
>
>
>
> intervention control difference - intervention control difference
> for males for females
> @ country -1 @ country-2
> --
> View this message in context:
>
http://spssx-discussion.1045642.n5.nabble.com/Three-Way-Anova-Post-Hoc-C> omparisons-tp3336188p3336188.html
> Sent from the SPSSX Discussion mailing list archive at Nabble.com.
>
> =====================
> To manage your subscription to SPSSX-L, send a message to
>
[hidden email] (not to SPSSX-L), with no body text except the
> command. To leave the list, send the command SIGNOFF SPSSX-L For a list
> of commands to manage subscriptions, send the command INFO REFCARD
>
> **********************************************************************
> This email and any files transmitted with it are confidential and
> intended solely for the use of the individual or entity to whom they
> are addressed. If you have received this email in error please notify
> the system manager.
> **********************************************************************
>
> =====================
> To manage your subscription to SPSSX-L, send a message to
>
[hidden email] (not to SPSSX-L), with no body text except the
> command. To leave the list, send the command
> SIGNOFF SPSSX-L
> For a list of commands to manage subscriptions, send the command
> INFO REFCARD
=====================
To manage your subscription to SPSSX-L, send a message to
[hidden email] (not to SPSSX-L), with no body text except the
command. To leave the list, send the command
SIGNOFF SPSSX-L
For a list of commands to manage subscriptions, send the command
INFO REFCARD