In a study of the adverse effects of x-rays among children, a retrospective cohort study was completed using records from several large children’s hospitals for the period of 1980 to 1985 10,000 children were selected as a representative population of ill children seen at the hospit during that time.

4. In a study of the adverse effects of x-rays among children, a retrospective cohort study was completed using records from several large children’s hospitals for the period of 1980 to 1985 10,000 children were selected as a representative population of ill children seen at the hospit during that time. Subjects were classified according to whether or not they received an x-ray during their stay in the hospital and were followed from their hospital stay through 2005 for t development of cancer. During the follow-up period, 49 incident cancers occurred in 3,263 children who had received an x-ray, and 47 incident cancers occurred in the 6737 children who had not received an x-ray during their hospitalization. Set up a contingency table for this study