Hi - this is now the "-e" option - see the randomise manual for more
information on this. For most simple designs you don't need this -
we'd need to know more about your model to be sure though.
Cheers, Steve.
On 28 Mar 2009, at 15:17, Agnieszka Burzynska wrote:
>
> Dear all
> I found this post below in the archives and wonder whether I need to
> use the –g flag for a desing similar to the one below. I dont find
> the -g option in the current version of randomise and therefore I am
> not sure what to do.
>
> My second question is: how much it matters to specify a group in the
> first “group” column in the Glm-GUI? Is it just for user’s own
> information? If I left all inputs with “1” but I specify groups in
> the Evs( for EV only one subgroup has non-zero values, etc) , does
> this first column still matter?
>
> Thank you,
> Aga
>
>
> >>> On 5 Mar 2008, at 16:55, :
> >>>
> >>>> > Hi Steve,
> >>>> >
> >>>> > Firstly I am not very familiar with the mathematics of design
> matrix
> >>>> > and contrast matrix. I am trying to get myself familiarized
> with it,
> >>>> > so kindly excuse me if any of my questions sound silly.
> >>>> >
> >>>> > I have two groups
> >>>> >
> >>>> > No of Controls: 13
> >>>> > No of Patients: 12
> >>>> > Behavioral data: Type1 (for both patients and controls)
> >>>> > Behavioral data: Type 2 (for both patients and controls)
> >>>> >
> >>>> > I would like to set up the randomise option in TBSS to do
> >>>> > correlation between the FA values and a behavioral measure
> (Actually
> >>>> > both - separately). There are two types of tests that I would
> like
> >>>> > to carry out.
> >>>> >
> >>>> > 1. Test whether the FA of all the subjects in both the
> groups
> >>>> > correlate with a behavioral measure.
> >>>> > 2. Contrast the behavioral correlation between the two
> groups.
> >>>> >
> >>>> > From some of the previous posts I initially assumed that I
> needed
> >>>> > two design matrices and one contrast matrix for both the
> tests. But
> >>>> > in the latest version of randomise that I downloaded it said
> that
> >>>> > confound regressors can be given in the main design matrix
> itself.
> >>>> > So I am assuming that we need only one design matrix and one
> >>>> > contrast matrix for both of the above tests that I had
> mentioned
> >>>> > above.
> >>>> >
> >>>> > If the above assumptions I have made are right then I will
> move on
> >>>> > with the design and contrast matrices that I have for both of
> the
> >>>> > above tests.
> >>>> >
> >>>> > Test 2 - Contrast the behavioral correlation between the two
> groups.
> >>>> >
> >>>> > So in this design matrix I had 2 groups and 4 EVs. In the
> groups
> >>>> > column I gave the value for first 13 subjects as 1 and for
> the rest
> >>>> > of the 12 subjects to be 2. The matrix given below is the
> design
> >>>> > matrix that I used for this testing. (b1-b25 is the behavioral
> >>>> > values for each of the 25 subjects.)
> >>>> >
> >>>> > EV1 EV2 EV3 EV4
> >>>> > b1 0 1 0
> >>>> > b2 0 1 0
> >>>> > b3 0 1 0
> >>>> > b4 0 1 0
> >>>> > b5 0 1 0
> >>>> > b6 0 1 0
> >>>> > b7 0 1 0
> >>>> > b8 0 1 0
> >>>> > b9 0 1 0
> >>>> > b10 0 1 0
> >>>> > b11 0 1 0
> >>>> > b12 0 1 0
> >>>> > b13 0 1 0
> >>>> > 0 b14 0 1
> >>>> > 0 b15 0 1
> >>>> > 0 b16 0 1
> >>>> > 0 b17 0 1
> >>>> > 0 b18 0 1
> >>>> > 0 b19 0 1
> >>>> > 0 b20 0 1
> >>>> > 0 b21 0 1
> >>>> > 0 b22 0 1
> >>>> > 0 b23 0 1
> >>>> > 0 b24 0 1
> >>>> > 0 b25 0 1
> >>>> >
> >>>> > From some of the past archives I found that the matrix that
> contains
> >>>> > the behavioral measures is the main matrix(used with -d) and
> the
> >>>> > matrix with the group membership information should be taken
> as the
> >>>> > confound matrix (used with -x).
> >>>
> >>> No, the group membership, which controls the exchangeability
> blocks,
> >>> should be passed in using the -g flag. There is no longer any
> need for
> >>> 'confound' matrices.
>
---------------------------------------------------------------------------
Stephen M. Smith, Professor of Biomedical Engineering
Associate Director, Oxford University FMRIB Centre
FMRIB, JR Hospital, Headington, Oxford OX3 9DU, UK
+44 (0) 1865 222726 (fax 222717)
[log in to unmask] http://www.fmrib.ox.ac.uk/~steve
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