One Quarter Fraction Design

2^k design with four factors/variables requires 16 experiments for the full replication. Therefore, quarter of the 16 experiments will results in only four experiments producing only three degrees of freedoms. Therefore, quarter fraction design is applicable for five or more factors/variables. In the one-half fraction 2^k-1 design, only one generator word or the defining relation was required to develop the design. Therefore, in one-quarter fraction 2^k-2 design, two generator word (or the defining relation) is required. Therefore, in a 2^k-p fractional design, p number of defining relation is required. A one-quarter fraction of five factors of resolution III design is provided in Table 9 using the defining relation I = ABD and I = BCE.