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Forum Newbie
Group: Forum Members
Last Login: 10/6/2008 5:37:16 PM
Posts: 2,
Visits: 7
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I'm trying to program a visual AX identity task, in which participants see a written stimuli (A, e.g., blow), a mask (e.g., XXXXXX), followed by a written stimulus (X, e.g., below) -- and are then asked to determine if A and X are identical (e.g., press 1 if identical, 2 if not). My experiment has 288 of these trials.
I'd like to add a second trial procedure to my experiment, in which participants are presented A, mask, X (as usual) -- but instead of determining if the items are identical -- I'd like them to be prompted after the presentation of X to spell either A or X (the spelling directions will be explicit for each trial, as to whether A or X should be spelled). I'd like them to type their response using the keyboard. These spelling trials should occur randomly (about one in every six normal experimental trials) -- so participants cannot predict when exactly the next spelling trial would occur.
I'm having difficulty implementing this design. Where do I place the spelling trial procedure in regard to the normal AX procedure?
How can I ensure a spelling trial is chosen randomly about once in every six trials, such that the spelling trials are sampled without replacement?
I can't seem to be able to figure out this programming after going through both the user's guide, and the samples online.
Thanks very much for your help,
Tracy
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