Four conditions - One pool of stimuli

[Emmet]

Hi David,

Thank you for your response- it was spot on. I also had a response
emailed to me from another member, so thank you too! I understand what
you are telling me although I am having one operational problem with
it:

>You can do this very easily
> with a nested List.  Just put all your stimuli in their own nested
> List, say, StimList.

So I have my nested list which I have called Stimlist and I currently,
for practice reasons, have one level which samples perfectly from my
slide object. Now when I add in a second level with another stimulus I
get this error message:

"Run-time Error (Line 295) -999: Factor Error:
Can't find procedure definition"

So it runs through fine until I add a second level to my nested list.
Considering I need 125 levels (pictures) to enter into this list, I am
slighty worries. I have been reading other topics and have seen that
perhaps I should enter all 125 pictures into one Level?

many thanks in advance,

Emmet

University of York





On Jun 16, 7:39 pm, David McFarlane <mcfar... at msu.edu> wrote:
> Emmet,
>
> Stock reminder:  1) I do not work for PST.  2) PST's trained staff
> takes any and all questions athttp://support.pstnet.com/e%2Dprime/support/login.asp, and they
> strive to respond to all requests in 24-48 hours -- this is pretty
> much their substitute for proper documentation, so make full use of
> it.  3) If you do get an answer from PST Web Support, please extend
> the courtesy of posting their reply back here for the sake of others.
>
> That said, here is my take...
>
> Not sure that I follow your question, so I will answer one that I
> can.  Suppose you have a pool of 125 stimuli and, *within any one
> session*, you want to sample 25 at a time randomly without
> replacement (i.e., no stimulus reused either within any sample of 25
> nor until all 125 stimuli are sampled).  You can do this very easily
> with a nested List.  Just put all your stimuli in their own nested
> List, say, StimList.  Set that List to Random.  Now, in any other
> List where you want to use stimuli from StimList, simply add StimList
> in the Nested column, and then use the attributes from StimList just
> as you normally would.  You can have one main List take 25 samples
> from StimList, and later take another 25 samples, and it will pick up
> right where it left off.  IOW, E-Prime essentially shuffles all 125
> stimuli, and then "draws" from that shuffled List until the List is
> exhausted, and then reshuffles the List and starts over.  Or, you can
> get other effects by changing settings under the List Reset/Exit tab.
>
> In general, just think of Lists (whether nested or not) as decks of
> playing cards, that's how I have come to understand them.  Think of
> nested Lists as just additional, separate decks of cards that get
> drawn from whenever you draw a row from a main List that names a
> nested List.  I have written about this elsewhere, if you search
> around you may find my earlier posts here or on the PST Forum, but
> here is another attempt...
>
> So, each "card" (row) in any "deck" (List) has some attribute values
> written on it; some of those may be the names of other decks (nested
> Lists) to draw from.  So, you start by shuffling all these decks as
> needed.  Then you draw a card from a "main" deck, and read off the
> attribute values written on it.  If any of these names another deck,
> you draw a card from those decks and read off those attribute values;
> once again, if any of these names another deck then you draw from
> that deck, etc.  When you are done you will have a set of attribute
> values to work with for that trial.  At the end of the trial you put
> all the cards that you drew onto a discard pile for each deck, and
> then draw new cards.  Whenever you exhaust any deck, you pick up its
> discard pile, reshuffle that deck as needed, and carry on.
>
> It gets a little more complicated than this because you can modify
> this behavior by changing the settings under the List Reset/Exit tab,
> but this is a pretty good first approximation.
>
> Now, if you want samples of 25 to take place *across* separate
> sessions, well, that is an entirely different and more complex
> matter.  Could be done, but no sense trying to explain that now.
>
> -- David McFarlane, Professional Faultfinder
> "For a successful technology, reality must take precedence over
> public relations, for nature cannot be fooled."  (Richard Feynman,
> Nobel prize-winning physicist)
>
> At 6/14/2011 12:18 PM Tuesday, you wrote:
>
>
>
> >Hi all,
>
> >I have battled through the entire user guide and I am definitely
> >getting places with my E Prime project but I have one sticking point I
> >hope you can help me with. I have a within-groups design withfour
> >groups (and one practice condition) and each condition will receive 25
> >picture slides. I think that my answer may lie within the nested lists
> >option but I'm struggling to a find a way to have each of the
> >conditionsrandomly sample (without replacement) their 25 pictures
> >from the same 125 picture list so that, in effect, each participant,
> >regardless of the counterbalancing ofconditionshas a unique ordering
> >of the stimuli from start through finish.
>
> >Please let me know if I have not explained myself clearly or if you
> >would like me to post up a screenshot or something (can I do that?)
>
> >many thanks in advance,
>
> >Emmet Clarke
>
> >University of York- Hide quoted text -
>
> - Show quoted text -

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