I am a PhD student in psychology runnning a study with some complicated randomization that I can't quite figure out how to implement in Qualtrics. I've described the math of what I need below, I'm just not sure how to make it happen in Qualtrics.
I have 93 blocks, divided _unevenly_ into 7 bins. Each block needs to be viewed by 50 participants, and each participant will see 10/93 blocks. The blocks need to be pulled from one of seven bins, in a quasi-random fashion. Specifically, because each bin has a different number of blocks in it (as you can see below) and I need each block to be seen 50 times across participants, blocks need to be randomly pulled from the bins at different probabilities. So, b/c of the # of blocks in each bin, out of the 10 blocks that each participant sees, on average 1.72 should be from Bin 1, 2.04 from Bin 2, etc. In other words, I need Qualtrics to randomly select each block (without repeats; e.g., I don't want a participant to see Block 17 more than once) from one of the bins based on those probabilities. So, for each block selected, there should be a 17.2% likelihood of it being from Bin 1, a 20.4% chance of it being from Bin 2, and so on for each block that is selected. Put differently, a block should be selected from Bin 1 17.2% of the time, but when a block is selected from Bin 1, it should be selected randomly and without replacement for a participant. Is this clear?
Is there a way to implement this in Qualtrics? I would really appreciate an answer to this as it's quite over my head.
Thank you!
A confused grad student
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