TC Chiang wrote:
> Dear Will:
> I want to follow the case...
> If there is only one task (like only task A in the case) and I want to
> do the conjunction [(uC-uI) & (cC-cI)] at the 2nd level. Should I use
> two sample t-test or full-factorial design that creates one factor with
> 2 levels? Are they the same?
>
Hi TC,
Yes, they're the same.
W.
> Best regards,
> TC
>
>
> On 02/04/2008, *Will Penny* <[log in to unmask]
> <mailto:[log in to unmask]>> wrote:
>
> [log in to unmask] <mailto:[log in to unmask]> wrote:
>
> Dear Will,
>
> How are you?
>
> I have a question regarding how to do conjunction analysis on the
> second level. Hope you can help me out. thanks!
>
> I had one group subjects who performed 3 tasks (A,B and C). In each
> task, they had 2 conditions (C and I) for both uncrossed (u) or
> crossed (c) hands, so totally four conditions which were uC, uI,
> cC,cI in each task and it was a 3*2*2 factorial design. In the first
> level, I have specified the contrasts, such as uI-uC, cI-cC,
> (uI+cI)-(uC+cC) and (cC+cI)-(uC+uI) for each task. Now I want to do
> conjunction analysis in the second level,e.g where is the common
> activation of uI-uC for the three tasks? When I clicked on the
> second
> level, which one I should select, full factorial or flexible
> factorial design? I guess I don't need to use one-sample or
> two-sample design. Thanks!
>
>
> For each subject generate three contrasts. These will
> be uI-uC for each of the three conditions.
>
> At the second level select a full factorial design. Then create
> a single factor with three levels. Your design will be a one-way ANOVA
> with three levels. You'll have three columns in your design matrix - one
> for each condition.
>
> After estimating the model parameters, select the three contrasts
> (select multiple contrasts by
> pressing the control button - or is it shift, shift/control I forget)
> [1 0 0], [0 1 0] and [0 0 1].
>
> Best wishes,
>
> Will.
>
> Regards,
>
>
> --
> William D. Penny
> Wellcome Trust Centre for Neuroimaging
> University College London
> 12 Queen Square
> London WC1N 3BG
>
> Tel: 020 7833 7475
> FAX: 020 7813 1420
> Email: [log in to unmask] <mailto:[log in to unmask]>
> URL: http://www.fil.ion.ucl.ac.uk/~wpenny/
> <http://www.fil.ion.ucl.ac.uk/%7Ewpenny/>
>
>
>
>
> --
> Lab. Neurobiology (Prof. Zeki's lab)
> Dept. Anatomy
> University College London
> Gower Street
> London, WC1E 6BT
>
> tel: +44 (0)207 679 2195 (UCL internal: 32195)
> fax:+44 (0)207 679 7316
--
William D. Penny
Wellcome Trust Centre for Neuroimaging
University College London
12 Queen Square
London WC1N 3BG
Tel: 020 7833 7475
FAX: 020 7813 1420
Email: [log in to unmask]
URL: http://www.fil.ion.ucl.ac.uk/~wpenny/
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