hi,
i need to have 2 blocks of bgr. that is, 3 groups should be randomized, then a new block starts and 10 other groups need to be randomized, but there must be NO randomization between the 3 groups and the 10 groups (just to explain: the first 3 groups belong to a practice session and the other 10 groups are the actual experiment, so i can't have trials of both types mixed).
thanks for your help (and sorry for the "bombing" of questions)