Hi,
In my event-related design expt with 3 conditions., each subject completes
6 blocks of memory tasks with 12 trials and each trial was divided into 4
events. Since I wanted to include only correct trials, I made a design
matrix with making incorrect trials as a separate condition and assigned a
contrast weight of "0" on those trials for subsequent data analysis. The
problem, however, is that there are a block or some blocks with no
incorrect trials for some subjects, resulting in empty cell in the design
matrix. I'm wondering if there is anyway that I can get away with treating
them as a separate variable instead of assigning vectors on each data file.
If not, what way do I approach?
Thanks,
Hwamee
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