Some Relations among the Blocks of Symmetrical Group Divisible Designs

Abstract

It is well known that if every pair of treatments in a symmetrical balanced incomplete block design occurs in $\lambda$ blocks, then every two blocks of the design have $\lambda$ treatments in common. In this paper it will be shown that a somewhat similar property holds for symmetrical group divisible designs. In the course of the investigation there will be introduced certain matrices which are of intrinsic interest.