Randomization with nested lists

[annekehaddad at gmail.com]

Hi there,

I'm having trouble with the randomization of some nested lists.

The overall structure of my experiment is as follows.

There are three stimuli, A, B, and C and 6 blocks. In each block, 
participants first "view" three pairs of stimuli, and then "rate" three 
pairs of stimuli. Within each block, each unique pair of stimuli (AB, AC, 
and BC) should appear exactly once in the "view" section and exactly once 
in the "rate" section. The position of each stimulus (left or right) should 
be counterbalanced within the "view" sections across the whole experiment 
and similarly within the "rate" sections across the whole experiment. 

Thus across the whole experiment, stimulus A should appear on the left 6 
times in the "view" context and 6 times in the "rate" context and similarly 
for the other stimuli - but I am having difficulty getting the position 
(left/right) to counterbalance properly.

My experimental setup looks something like this:

Experiment
 -BlockList (ThreeViewTrialsProc,ThreeRateTrialsProc) 12 samples (6 cycles 
x 2 samples/cycle), 1 cycle equals 2 samples, seq. selection
    -ThreeViewTrialsProc
       -PairingsList1 (three rows showing the three pairs) 3 samples, 1 
cycle equals 3 samples, random selection 
            -nested within this LeftRightList1 (two rows showing the l/r 
orientations) 1 sample, 1 cycle equals 2 samples, random selection
               -ViewProc   
    -ThreeRateTrialsProc
       -PairingsList2 (three rows showing the three pairs) 3 samples, 1 
cycle equals 3 samples, random selection 
            -nested within this is LeftRightList2 (two rows showing the l/r 
orientations) 1 sample, 1 cycle equals 2 samples, random selection
               -RateTrialProc

I get the right number of pairs of each type, but I seem to get one too 
many of, for example, A on the left. What am I doing wrong?

Many thanks in advance for your help.

Anneke

-- 
You received this message because you are subscribed to the Google Groups "E-Prime" group.
To unsubscribe from this group and stop receiving emails from it, send an email to e-prime+unsubscribe at googlegroups.com.
To post to this group, send email to e-prime at googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/e-prime/10e291fa-0c55-41a6-bf35-85ea17c53609%40googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://listserv.linguistlist.org/pipermail/eprime/attachments/20140624/dbde565b/attachment.htm>