in the 1990s, it was generally believed that genetic abnormalities affected about 6% of a large 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, which could have important implications for health insurance companies. a recent study examined 446 randomly selected children and found that 37 of them showed signs of a genetic abnormality. (a) which hypotheses should be used to test if the proportion of genetic abnormalities has increased in recent years?