Mat 152 A psychologist is developing a new training program which is supposed to improve short-term memory. To test if it works, she uses a matching card game and times how long a person takes to correctly match all card pairs. She finds 10 sets of twins. For each set of twins, she randomly chooses one to get the new training, and then both twins separately take the memory test and are timed.. Is it randomized block, completely randomized or matched pairs