Posted by
Paul Mcgeoghan on
Feb 07, 2007; 11:02am
URL: http://spssx-discussion.165.s1.nabble.com/repeated-measures-custom-contrasts-for-linear-trends-tp1073671p1073677.html
On Mon, 5 Feb 2007 09:08:35 -0500, Statisticsdoc <
[hidden email]>
wrote:
>Paul,
>
>Replace Polynomial with Special in the WSFACTOR line, and supply a set of
>contrasts that you specify. Since you have a significant cubic
interaction,
>you should consider more than just the linear trend. Testing just the
>linear trend might be misleading if there are cubic or other higher order
>effects.
>
>HTH,
>
>Stephen Brand
>
>For personalized and professional consultation in statistics and research
>design, visit
>www.statisticsdoc.com
>
>
>-----Original Message-----
>From: SPSSX(r) Discussion [mailto:
[hidden email]]On Behalf Of
>Paul Mcgeoghan
>Sent: Monday, February 05, 2007 8:27 AM
>To:
[hidden email]
>Subject: Re: repeated measures custom contrasts for linear trends
>
>
>Stephen,
>
>The Tests of Within-Subjects effects Greenhouse-Geisser is significant .040
>and Huynh-Feldt is
>significant .027 for the MOVES*IAC interaction.
>
>The Tests of Within Subjects Contrasts indicates a significant cubic effect
>(.039) for MOVES*IAC.
>
>So yes.
>
>Paul
>
>
>==================
>Paul McGeoghan,
>Application support specialist (Statistics and Databases),
>University Infrastructure Group (UIG),
>Information Services,
>Cardiff University.
>Tel. 02920 (875035).
>
>>>> "Statisticsdoc" <
[hidden email]> 05/02/2007 13:17:56 >>>
>Paul,
>
>Do you have a significant interaction between MOVES and IAC (i.e., is there
>evidence that the slope of the within-subject factor varies as a function
of
>the between-subject factor)?
>
>Best,
>
>Stephen Brand
>
>For personalized and professional consultation in statistics and research
>design, visit
>www.statisticsdoc.com
>
>
>-----Original Message-----
>From: SPSSX(r) Discussion [mailto:
[hidden email]]On Behalf Of
>Paul Mcgeoghan
>Sent: Monday, February 05, 2007 6:02 AM
>To:
[hidden email]
>Subject: repeated measures custom contrasts for linear trends
>
>
>Hi,
>
>I have a customer with a within-subject factor (MOVES) with 10 levels and a
>between subject factor
>with 3 levels (IAC).
>
>He wants to test if there is a linear trend at each of the 3 between
subject
>factor levels.
>
>What would be the syntax for this?
>
>I currently have the syntax below:
>
>GLM
> moves1 moves2 moves3 moves4 moves5 moves6 moves7 moves8 moves9 moves10 BY
>iac
> /WSFACTOR = trial 10 Polynomial
> /METHOD = SSTYPE(3)
> /EMMEANS = TABLES(iac) COMPARE ADJ(BONFERRONI)
> /EMMEANS = TABLES(trial) COMPARE ADJ(BONFERRONI)
> /EMMEANS = TABLES(iac*trial) COMPARE(iac) ADJ(bonferroni)
> /EMMEANS = TABLES(iac*trial) COMPARE(trial) ADJ(bonferroni)
> /PRINT = DESCRIPTIVE
> /CRITERIA = ALPHA(.05)
> /WSDESIGN = trial
> /DESIGN = iac .
>
>Thanks,
>Paul
>
>
>==================
>Paul McGeoghan,
>Application support specialist (Statistics and Databases),
>University Infrastructure Group (UIG),
>Information Services,
>Cardiff University.
>Tel. 02920 (875035).
Hi,
Having found that a cubic interaction exists between the within subject
factor MOVES and the between subject factor IAC, I click on Options and
Transformation Matrix.
This gives me the M matrix in the output (taking the coefficients from
that) and using the L matrix below will allow me to look at whether there
is a linear, quadratic or cubic trend at each individual Between Subject
Factor level.
Is this correct syntax and if not, what is the syntax to use?
GLM
moves1 moves2 moves3 moves4 moves5 moves6 moves7 moves8 moves9 moves10 BY
iac
/WSFACTOR = moves 10 Polynomial
/lmatrix 'Nesting within iac(1)' all 1 1 0 0
/lmatrix 'Nesting within iac(2)' all 1 0 1 0
/lmatrix 'Nesting within iac(3)' all 1 0 0 1
/mmatrix 'Linear trend using normalized metric'
all -.495 -.385 -.275 -.165 -.055 .055 .165 .275 .385 .495;
'Quadratic trend using normalized metric'
all .522 .174 -.087 -.261 -.348 -.348 -.261 -.087 .174 .522;
'Cubic trend using normalized metric'
all -.453 .151 .378 .335 .130 -.130 -.335 -.378 -.151 .453
/CONTRAST (iac)=Polynomial
/METHOD = SSTYPE(3)
/PLOT = PROFILE( moves*iac )
/EMMEANS = TABLES(iac) COMPARE ADJ(BONFERRONI)
/EMMEANS = TABLES(moves) COMPARE ADJ(BONFERRONI)
/EMMEANS = TABLES(iac*moves)
/PRINT = TEST(MMATRIX)
/CRITERIA = ALPHA(.05)
/WSDESIGN = moves
/DESIGN = iac .