Calling a second trial procedure within a procedure

[Tracy]

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?

Thanks very much for your help,
Tracy
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups "E-Prime" group.
To post to this group, send email to e-prime at googlegroups.com
To unsubscribe from this group, send email to e-prime+unsubscribe at googlegroups.com
For more options, visit this group at http://groups.google.com/group/e-prime?hl=en
-~----------~----~----~----~------~----~------~--~---