Title
Designing an Experiment in Two Blocks
Speaker
John Morgan, Virginia Tech
Abstract
Faced with cost, time, or other pressures to keep an experiment small, blocking can be an effective tool for increasing precision of treatment comparisons. The simplest implementation of blocking is a division of experimental units into two equi-sized subsets, allocating one degree of freedom to explain unit heterogeneity. Small experiments will have block size $k$ smaller than the number of treatments $v$ being compared. This talk attacks the problem of optimal allocation of treatments to two small, equi-sized blocks. Solutions depend on the optimality criterion employed as well as the ratio $\frac{k}{v}$.
This work evolved in response to a design request from an engineer working with vehicle traction on sandy surfaces. The talk begins with a discussion of that experiment and the evolution of its design. We will touch on practical issues such as unrealistic expectations, the destructive effects of sloppy experimental procedure, and the gap between textbook design and the engineer's needs.
Meet the speaker in Room 212 Cockins Hall at 4:30 p.m. Refreshments will be served.
