mnli premise: Following the approach of the Section 812 Prospective Report, we estimated the percentage change in the prevalence rate for chronic bronchitis using the estimated coefficient from Schwartz's study in a C-R function, and then applied this percentage change to a baseline incidence rate obtained from another source. hypothesis: Following the approach of the report, we guessed that the percentage change in the prevalence rate for chronic bronchitis using the coefficient from the study.