4. Consider the data from a cohort study to determine the risk of urethral strictures in male offspring of dim-exposed pregnant women, as reported by Henderson et al (1976). From a sample of 111 unexposed pregnancies, 17 offspring with symptoms of urogenital tract abnormalities and two off spring with problems of passing urine were found. From another sample of 225 exposed pregnancies, the numbers of offspring with the above two symptoms are 55 and 29, respectively. Carry out a test of possible association between the risk of urethral strictures in male offspring and diethystibesterol-exposed pregnant women. Calculate the associated 95% CIs and interpret your ndings