# How to report orthogonal contrast codes?

by CogNeuro123   Last Updated August 13, 2019 20:19 PM - source

In my linear mixed effects model, I had a significant interaction, I followed up the interaction with orthogonal contrast codes to see where the difference was.

How do I report my findings, other than a p-value? Do I need to report a t or F statistic as well?

`````` Type III Analysis of Variance Table with Satterthwaite's method
Sum Sq Mean Sq NumDF  DenDF  F value    Pr(>F)
group                      3566    1783     2  90.01   1.0697   0.34743
session                   30588   30588     1 629.03  18.3504 2.125e-05 ***
trialtype               3004359 1001453     3 629.03 600.7995 < 2.2e-16 ***
group:session             13907    6953     2 629.03   4.1715   0.01586 *
group:trialtype            6066    1011     6 629.03   0.6065   0.72522
session:trialtype         11775    3925     3 629.03   2.3547   0.07094 .
group:session:trialtype    6154    1026     6 629.03   0.6153   0.71815
``````

For the contrast code, I left the last two as all 0s because I was only interested in compared Group 1 pre-post (1-4) Group 2 pre-post (2-5) and Group 3 pre-post (3-6). Please correct if this is wrong.

``````contrastmatrix<-cbind(c(1,0,0,-1,0,0),c(0,1,0,0,-1,0),c(0,0,1,0,0,-1),c(0,0,0,0,0,0),
c(0,0,0,0,0,0))
contrasts(pairwisegp)<-contrastmatrix

summary.lm(aov(rt~pairwisegp))

Coefficients: (2 not defined because of singularities)
Estimate Std. Error t value Pr(>|t|)
(Intercept)  302.910      3.588  84.429   <2e-16 ***
pairwisegp1    5.431      6.210   0.875   0.3821
pairwisegp2    2.016      6.223   0.324   0.7460
pairwisegp3   12.373      6.210   1.993   0.0467 *
pairwisegp4       NA         NA      NA       NA
pairwisegp5       NA         NA      NA       NA
``````
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