Problem 13.25 Analyze the data of the preceding problem as a half replicate with defining relation I = ABC. That is, compute the fractional replicates lA, lB, lC and the correspond[1]ing sum of squares; then compute SST and SSE for this half replicate. Determine the proportion of variability that is explained by each main effect and comment on whether or not your results are consistent with those obtained from the complete factorial.