A Note on Partitioning a Set of Normal Populations by Their Locations with Respect to Two Controls

The problem of partitioning a set of normal populations with respect to one control has been considered by Tong (1969). This note points at the possibility of using two controls which gives a partitioning into three disjoint groups. The procedure utilizes Tong's tables. It is also stated that the procedure can be used for mixed randomized block designs with a certain symmetry. An extension to more than two controls is also mentioned.