Sampling without replacement

Comments

• sebastiaan

  August 2016

  Hi Morgan,

  The structure of your experiment is not really clear to me. Could you upload it (you can attach it to a comment) so I can take a look?

  Cheers,
  Sebastiaan

  
  
  Check out SigmundAI.eu for our OpenSesame AI assistant!
  
• morgan19

  August 2016

  How do I upload an .osexp file into the comments? I'm only seeing an external link for URL and image URL? Or did you want the general script of the experiment?
• sebastiaan

  August 2016

  

  You can just upload it by selecting an osexp file instead of an image through the attachment dialog (which, I admit, is a bit confusing).

  
  
  Check out SigmundAI.eu for our OpenSesame AI assistant!
  
• morgan19

  August 2016

  I've checked on both a PC and Mac, and 3 different web browsers and I'm not able to get a file upload through the attachment dialog. They all strictly offer an Image URL attachment. Maybe it's a function that got lost in the US version of the website? I'm not sure!
• sebastiaan

  August 2016

  Oops, it was a permission issue: Regular members weren't allowed to upload files. You should be able to upload the experiment now.

  
  
  Check out SigmundAI.eu for our OpenSesame AI assistant!
  
• morgan19

  August 2016

  

  I'm specifically looking for a way to have no replacement when I'm sampling from the tables (like the one I screenshot). I don't want any of the equations or letters to be repeated while doing one letter sequence. For example, the 2_Loop is a loop that creates a 2 letter sequence OSpan, where the participant is shown an equation, then a letter, then another equation, then another letter, and finally has to recall the 2 letters in the correct order. Within that 2 letter sequence, I don't want there to be a repeated equation or a repeated letter, but I can't figure out a way to do that.
• eduard

  August 2016 edited August 2016

  Hi Morgan,

  I don't think you can make your experiment with relying only on the loop tables, at least not in an easy way. I recommend you select the trials to run from within an inline_script. This requires that you have your variables stored in some data container. As all three (equation, correct_response, and letter) belong together, it makes sense to store them in a dictionary, e.g. trial_one = dict(equation='1+4 =5',cor_resp = 'left',letter='F'). However, if you could also just have three separate lists, and use the same indices to operate on them. This should also make sure that you don't mix them up. Here some code that selects two trials with the restrictions you mentioned.

  import random
  
  # a list with all your equations (I use only 4, for brevity)
  equations = ['1+4=5','1+5=7','3+6=8','2+4=5']
  # same for correct_response and letter. Make sure you don't mess up the order!
  correct_response = ['left','right','left','right']
  letter = ['F','G','F','G']
  
  # choose the first equation and letter
  idx1 = random.choice(range(len(equations)))
  eq1 = equations[idx1]
  let1 = letter[idx1]
  
  # Keep on sampling the 2nd equation and letter as long as either matches the first equivalent
  # once both letters and equations are unique, set the correct_response and break the loop
  while True:
      idx2 = random.choice(range(len(equations)))
      eq2 = equations[idx2]
      let2 = letter[idx2]
      if let2 != let1 and eq1 != eq2:
          cr1 = correct_response[idx1]
          cr2 = correct_response[idx2]
          break
  

  I hope this is useful.

  Good luck,

  Eduard