In 2003 the Journal of the American Medical Association reported a study examining the possible impact of air pollution caused by the 9/11 attack on New York's World Trade Center on the weight of babies. Researchers found that 8% of 182 babies born to mothers who were exposed to heavy doses of soot and ash on September 11 were classified as having low birth weight. Only 4% of 2300 babies born in another New York City hospital whose mothers had not been near the site of the disaster were similarly classified. Does this indicate a possibility that air pollution might be linked to a significantly higher proportion of low-weight babies?
a) Test an appropriate hypothesis and state your conclusion.
b) If you concluded there is a difference, estimate that difference with a confidence interval and interpret that interval in context.