That is correct.
doug
Jose Luis Cantero Lorente wrote:
Dear all,
I have a data set with a diagnosis factor (three groups) and four covariates, the fsgd.txt file is pasted below:
GroupDescriptorFile 1
Title Thickness-subj
Class control
Class EHM
Class NEHM
variables zAge zGender zCTlh zCFF
Input c_12 control 0.15 1 -0.66 0.24
Input c_13 control -0.64 1 1.02 -0.09
Input c_14 control 0.28 2 1.14 1.93
Input ehm_1 EHM 0.81 2 0.22 1.17
Input ehm_10 EHM 1.47 2 -0.34 -0.15
Input ehm_16 EHM 1.34 1 -2.18 -0.09
Input nehm_10 NEHM 0.81 2 -0.8 1.11
Input nehm_11 NEHM -0.77 1 -0.06 0.59
Input nehm_13 NEHM -0.64 1 0.63 0.09 ...
The contrast to test whether intercepts are different between groups (ANOVA) would be:
1 -1 0 0 0 0 0 0 0 0 0 0 0 0 0
1 0 -1 0 0 0 0 0 0 0 0 0 0 0 0
whereas if I want to test for slope differences between groups for the zCFF variable I should write:
0 0 0 0 0 0 0 0 0 0 0 0 1 -1 0
0 0 0 0 0 0 0 0 0 0 0 0 1 0 -1
_
An example of post hoc contrast for the former case would be
1 -1 0 0 0 0 0 0 0 0 0 0 0 0 0
and for the latter
0 0 0 0 0 0 0 0 0 0 0 0 1 -1 0
I just need confirmation that everything is fine (or wrong).
Thanks in advance for your help.
Best regards,
Jose_
Jose L. Cantero, Ph.D. Laboratory of Functional Neuroscience Department of Physiology, Anatomy and Cell Biology University Pablo de Olavide Ctra. de Utrera, Km.1 41013 - Seville
- Spain -
Phone: +34 954 977433 Fax: +34 954 349151 Email: jlcanlor@upo.es http://www.upo.es/neuroaging/es/
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