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randomizing on distributions

  1. #1

    randomizing on distributions

    Hi,
    I am trying to create an experiment that will link a distribution to a specific list of words. I want one word to be presented 5 time, one 3 and the other three words once each.
    For example the words are apple, orange, pear, grape and peach.
    For one participant peach would appear 5 time and in another only once. the same would hold for all of the words.
    I want the order of presentation of the words to be random, as well as the distribution assignment.
    I would like the assignment of the words to distribution to be random, but I have not been able to figure out how to do so.
    Is such a situation possible in DirectRT?

  2. #2
    jarvis24 Blair Jarvis, Administrator
    Try this:

    Create a stimlist with the 5 words and call it something like mylist.txt.

    On the first trial, randomly draw one from the list, using $mylist. Then add 4 trials that repeat that stimulus, using the syntax like ?b1t1s1 (see link below for repeating a particular stimulus on a subsequent trial)

    On the sixth trial, randomly draw another word from the list using $mylist. This time add just 2 trials that repeat that stimulus, using the syntax like ?b1t6s1.

    Finally, add 3 more trials--each randomly drawing from the stimlist, using $mylist. These will each be presented just once.

    Finally, assign all the trials a WGR value of 1 to randomize their order.

    Take a look at the section on "using previous stim" in the users guide:

    www.empirisoft.com/directrt/help/directrt_samples_of10_using_previous_stim.htm

    Let me know if you have any trouble with it.