22. Abnormalities In the 1980s, it was generally believed that congenital abnormalities affected about 5% of the nation’s children. Some people believe that the increase in the number of chemicals in the environment has led to an increase in the incidence of abnormalities. A recent study examined 384 children and found that 46 of them showed signs of an abnormality. Is this strong evidence that the risk has increased? a) Write appropriate hypotheses. b) Check the necessary assumptions and conditions. c) Perform the mechanics of the test. What is the P-value? d) Explain carefully what the P-value means in context. e) What’s your conclusion? f) Do environmental chemicals cause congenital abnormalities? 23. Absentees The National Center