Some firms comprehend the enormous potential that exists for providing services to the growing low income segment. Operating in the low-income market has numerous complications, such as designing an efficient distribution and servicing system, offering simple and “easy to consume” products,...

We look at fitting regression models using data from stratified cluster samples when the strata may depend in some way on the observed responses within clusters. One important subclass of examples is that of family studies in genetic epidemiology, where the probability of selecting a family into...