Let's say I have an experiment with two factors A and B, each with a number of different levels.
I want participants to
- see all levels of factor A exactly $n$ times,
- never see a level of B twice
How would I generate a test plan that assigns me $x$ users to the various combinations of A and B given the above constraints?
More specifically, suppose I have 5 pairs of speakers (factor A) and 10 audio samples (factor B). I would like each speaker to be tested by 12 people. I therefore need to recruit 60 ($5 \times 12$) people to listen to all pairs of speakers. Since the audio samples are so long they couldn't possibly listen to all of them. How do I assign them to the audio samples?
I tried starting with a smaller version.. 3 speakers, 6 audio sources, and 6 listeners (A through F), meaning I get two listeners per speaker. But how can I generalize this?
Perhaps I'm missing the terminology to look it up somewhere, but I only got as far as creating the full test matrix, which isn't really helpful here.