The black co diagonal is probably an effect of sphericity correction, after which the designmatrix is also filtered.E.g. it would be an effect of telling SPM that the pre and post sessions are not independent.

best
Torben

On 1 May 2018, at 01.29, Karina Quevedo <[log in to unmask]> wrote:

Hi Manfred,

The results that we are getting from this two batch are actually different. This is a second-level analysis and even though we are calculating the first level the same way, in matrix 1, clearly something is been excluded, but in matrix 2, it is included.
The last column is a continuous covariate.

The first 6 white blocks refer to a pre condition, and the next are post condition.
Within each time, there are 2 within subject factors (1 and 2). 1 with 2-levels (1a and 1b) and 2 with 3-levels (2a, 2b, 2c). 

Column 1: Pre, 1a, 2a
Column 2: Pre, 1a, 2b
Column 3: Pre, 1a, 2c
Column 4: Pre. 1b, 2a
Column 5: Pre, 1b, 2b
Column 6: Pre, 1b, 2c
Column 1: Post, 1a, 2a
Column 2: Post, 1a, 2b
Column 3: Post, 1a, 2c
Column 4: Post. 1b, 2a
Column 5: Post, 1b, 2b
Column 6: Post, 1b, 2c

Our question is, what does the black diagonal in matrix 1 mean compared to matrix 2?

Thank you.

Warmly,
Karina


On Fri, Apr 27, 2018 at 2:36 AM, Manfred Klöbl <[log in to unmask]> wrote:

Dear Karina,

to fully answer your question, you need to describe what the single rows and columns are. If you are just wondering why the result is the same (if I get it correctly), this might be because your contrast only deals with the last column, which seems to be exactly the same. When the matrices only differ in the dark diagonals, the difference only affects the distribution of the means from line 1 to ~50, ~50 to ~100 and so on. Hence, only the effects you are not interested in, are handled differently.

Best,
    Manfred


Am 26.04.2018 um 23:33 schrieb Karina Quevedo:
Dear SPMers,

I have a question about design matrix. Both of the design matrix below is running the exact same thing.

What is the difference of the two dark diagonal line? 
<Design Matrix.jpg>
Thank you.

Best,
Karina

--
Karina Quevedo, Ph.D., L.P.
Assistant Professor. Division of Child and Adolescent Psychiatry
Room F260
University of Minnesota. Department of Psychiatry
612-273-9761 Fax: 612-273-9779 



--
Karina Quevedo, Ph.D., L.P.
Assistant Professor. Division of Child and Adolescent Psychiatry
Room F260
University of Minnesota. Department of Psychiatry
2450 Riverside Avenue, Mpls, MN 55454
612-273-9761 Fax: 612-273-9779