2 paradigm questions

[Rachel Mitchell]

Hi
I'm a new e-prime user (only got it this week) so apologies for lasking what
may be stupid questions

There are 2 things I need to do, but can't figure out how to achieve them

I plan to play sound files in an e-prime experiment
At the moment, my stimuli are arranged in subfolders according to type. I
have 4 such folders, let's call them type1 through to 4. Each subfolder
contains a bank of some 70 exemplars of that type of stimuli

In the first block of my expt I want e-prime to randomly present 20 of my
auditory stimuli. However, I want to make sure that equal numbers of each of
the 4 types of stimuli are selected
I have found out how to select 20 examples from a single folder of 70
stimuli, but not how to do what I outline above

Now for my 2nd problem. In block 1 subjects have to identify the tone of
voice the speaker is using
But in block 2 they have to identify the tone of voice the speaker used in
the previous sentence
And in block 3 they have to identify the tone of voice the speaker used in
the stimuli before the previous one.
For block 1, in my trial list I would have a column titled correct answer
and indicate in that column the correct answer for each of the bank of
stimuli
But, since the order of stimuli is random in blocks 2 and 3, I don't know
what stimuli the computer will have presented previously. So for the
purposes of gathering accuracy data, how would could I indicate in the
correct answer column of blocks 2 and 3 what the tone of voice of the
previous or 2 previous stimuli was?

I hope I've outlined my problem clearly enough.
N-back tasks are fairly standard fodder, so I'm hoping one of you has had to
do this kind of thing before
I therefore thank you in anticipation of any help you might be able to give
me

Regards
Rachel

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Dr Rachel L. C. Mitchell
Lecturer in Cognitive Psychology, University of Reading
Honorary Research Fellow, Institute of Psychiatry

Correspondence Address:
School of Psychology
Whiteknights Road
University of Reading
Reading
Berkshire
RG6 6AL

Tel: +44 (0)118 378 8523
Direct Dial: +44 (0)118 378 7530
Fax: +44 (0)118 378 6715
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