  We explore the problem of deriving a posteriori probabilities of being
defective for the members of a population in the non-adaptive group testing
framework. Both noiseless and noisy testing models are addressed. The
technique, which relies of a trellis representation of the test constraints,
can be applied efficiently to moderate-size populations. The complexity of the
approach is discussed and numerical results on the false positive probability
vs. false negative probability trade-off are presented.
