onsider a 25 experiment (five main effects A,B,C,D,E ). Suppose that it was necessary to run this design in 8 blocks of 4 runs/treatments per block. It was decided to confound ABC , BDE , ACE . Identify which treatment combinations belong to the principal block (the block containing treatment combination (1) ) and which treatment combinations belong to the block containing treatment combination a . Treatment combinations are labeled using lower case letters for all factors that are at their High level. So, for example (1) means that A,B,C,D,E are all at their low level, a means that A is at its high level and the rest are at their low level. Treatment bce means that B,C,E are at their high level and A,D are at their low level. You are only required to find the treatment combinations that belong to the two blocks indicated. You are not required to say anything about the other six blocks in the design.