Statistica Sinica 14(2004), 1075-1084
SOME NEW THREE-LEVEL ORTHOGONAL MAIN
EFFECTS PLANS ROBUST TO MODEL UNCERTAINTY
Pi-Wen Tsai, Steven G. Gilmour and Roger Mead
National Health Research Institutes,
Queen Mary, University of London
and The University of Reading
Abstract:
In this paper, we list some new orthogonal main effects
plans for three-level designs for 4, 5 and 6 factors in 18 runs
and compare them with designs obtained from the existing 
orthogonal array. We show that these new designs have better
projection properties and can provide better parameter estimates
for a range of possible models. Additionally, we study designs in
other smaller run-sizes when there are insufficient resources to
perform an 18-run experiment. Plans for three-level designs for 4,
5 and 6 factors in 13 to 17 runs are given. We show that the
best designs here are efficient and deserve strong
consideration in many practical situations.
Key words and phrases:
Factor screening, fold-over designs, fractional replicate,
orthogonal array, projection.