A major court case on the health effects of drinking contaminated water took place in the town of Woburn, Massachusetts. A town well in Woburn was contaminated by industrial chemicals. During the period that residents drank water from this well, there were 16 birth defects among 414 births. In years when the contaminated well was shut off and water was supplied from other wells, there were 3 birth defects among 228 births. The plaintiffs suing the firm responsible for the contamination claimed that these data show that the rate of birth defects was higher when the contaminated well was in use. How statistically significant is the evidence? What assumptions does your analysis require? Do these assumptions seem reasonable in this case?

Community Answer

【General guidance】The answer provided below has been developed in a clear step by step manner.Step1/2Given that Let us consider to take x1=16 x2=3n1=414 n2=228Hypothesis Test:Null hypothesis test H0:p1=p2no significance difference between the two proportion of defects of births before and after closing camminated well.Alternative hypothesis test H0:p1>p2 The proportion of defects is higher when the communated well was in use.Explanation:Please refer to solution in this step.Step2/2Sample proportion: p1=x1/n1n p2=x2/n2 p1=16/414 p2=3/228 p1=0.0386 p2=0.0131Test statistic: Z=p1-p2/\( \mathrm{{\sq ... See the full answer