I want to create an experiment that has three groups of treatments -the first one is three sets of 12 questions, the second one three sets of 12 questions and the third 4 sets of 12 questions). I want to randomly present ONLY one set of 12 questions out of each group and the order the groups are presented should be random. Then the experiment has to stop.
How do I do this? I've tried everything I could think of but without any success. Any help is much appreciated. Thank you!