Dear Cherry I our analysis, the gender as a Covariate, so all female groups assigned 0 in the matrix, following is new matrix: 1 -1 -1 -1 -1 -1 0 0 -1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1-1 -1 0 -1 -1 -1 -1 -1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 -1 -1 -1 -1 -1 0 0 -1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1-1 -1 0 -1 -1 -1 -1 -1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
is it correct?
Any help will be very appreciated.
Best wishes,
Bo Xiang
At 2012-11-18 10:51:07,"Yizhou Ma" ym850@nyu.edu wrote: Hi Bo,
I'm definitely not an expert of this, but I see that you really nead some help, so I tried to look at your matrix. From my humble opinion it doesn't look correct. Firstly, the first 9 groups are male groups and the last 9 are female groups. Then why are all female groups assigned 0 in the matrix? Secondly, since the interaction you are interested in have a df of 4, do you think maybe you should have 4 rows rather than 8 in your matrix?
Cherry
On Sat, Nov 17, 2012 at 9:21 PM, xiangbo_2010 xiangbo_2010@126.com wrote:
Hi Freesurfer experts, I'm very sorry to bother you, but I am very confused with the following questions:
My experimental design includes three discrete factors: factor 1 with three levels (A,B,C ); factor 2 with three levels (O,P,Q); gender (F, M), and one covariate.
So I can get 18 classes: FAO, FAP,FAQ,FBO,FBP,FBQ,FCO,FCP,FCQ,MAO, MAP,MAQ,MBO,MBP,MBQ,MCO,MCP,MCQ. I want to perform the interaction between factor 1 and factor 2 regressing out the effect of gender and one covariate, but I don't know the rules for setting the contrasts for the F-test. The contrast matrix I used is:
1 1 1 -1 -1 -1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
1 -1 0 1 -1 0 1 -1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
1 1 1 0 0 0 -1 -1 -1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
1 0 -1 1 0 -1 1 0 -1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 1 1 1 -1 -1 -1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 1 -1 0 1 -1 0 1 -1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 1 1 1 0 0 0 -1 -1 -1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 1 0 -1 1 0 -1 1 0 -1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
is it correct?
Any help will be very appreciated.
Best wishes,
Bo Xiang
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