Characteristics of the Study Population Our study population included 277 kids between the age groups of 4 and 12 years who were PCR-positive for pertussis, 3318 PCR-negative controls, and 6086 matched controls. Lists characteristics of the case controls and patients. Older age was connected with a higher %age of positive PCR tests: 4.5 percent among 6-year-old children, 12.2 percent among 8-year-old children, and 18.5 percent among 10-year-old children.And Schering-Plough Corp. Stated Wednesday they will pay out $5.4 million to settle civil claims that the companies covered up test outcomes that cast question on the potency of two blockbuster cholesterol medicines. The ongoing companies settled with attorneys general from 35 states and the District of Columbia. The investigation centered on claims the companies kept the results from unfavorable studies tranquil, violating consumer protection laws. Merck, Whitehouse Station, N.J., and Schering-Plough, Kenilworth, N.J., can pay back the costs of the investigation, but need not make other obligations or admit wrongdoing or liability.