Inequivalent projections of Hadamard matrices of orders 16 and 20

Screening designs are useful for situations where a large number of factors (q) is examined but only few (k) of these are expected to be important. It is of practical interest for a given k to know all the inequivalent projections of the design into the k dimensions. In this paper we give all the inequivalent projections of inequivalent Hadamard matrices of orders 16 and 20 into k=3, 4 and 5 dimensions, as well as their frequencies. Copyright Springer-Verlag 2003