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Hi FSL Guru's

        I've painted myself into a really complicated repeated measures,
        nested design, and I'd appreciate some feedback about whether the
        EV's and contrasts I've set up for my second level analysis are
        correct.

        This is a dual-task task visual attention study, so we have each
        of the dual task conditions in a single task form. Because we
        have some repeated measures within the dual task condition,
        however, we end up with an unbalanced (nested design).
        The conditions are

        A (single task)
                1 center task
                2 peripheral vision task, proximal to fixation
                3 peripheral vision task, distal to fixation

        B (dual task)
                1 center task + proximal peripheral task
                2 center task + distal peripheral task


        I've set up my matrix using dummy variables, such that

        X1 = 1 single, 0 else
        X2 = 1 center single, 0 else
        X3 = 1 proximal peripheral single, 0 else
        X4 = 1 proximal dual single, 0 else
        X5 = subject 1
        X6 = subject 2
        X7 = subject 3


        The EV Matrix ends up being

        A1 1 1 0 0 1 0 0
        A2 1 0 1 0 1 0 0
        A3 1 0 0 0 1 0 0
        A4 0 0 0 1 1 0 0
        A5 0 0 0 0 1 0 0

        And my contrasts are structured

        single task 1 0 0 0 0 0 0
        dual task   0 0 0 .5 .165 .165 .165
        center single 0 1 0 0 0 0 0
        etc.


        My biggest concern is that my EV's are set up using a very simple
        "on/off" matrix, but if I set it up in the more traditional manner
        (i.e. 1 for single task, -1 for dual task) I find I can't make the
        maths work out for the contrasts I need. (I'll be happy to accept
        feedback about any errors, however).

        Thanks in advance for any help you can give.

        Paige