An environmental group is suing a manufacturer because chemicals dumped into a nearby river may be harming fish. A sample of fish from upstream (no chemicals) is compared with a sample from downstream (chemicals), and a 95% confidence interval for the difference in proportions of healthy fish is 0.01 to 0.11 (with a higher proportion of healthy fish upstream).
First, interpret this interval. The statistician for the manufacturer produces a 99% confidence interval ranging from -0.01 to +0.13 and tells the judge that because it includes 0 and because it has higher accompanying confidence than the other interval, we can't conclude that there is a problem. Comment on the statistician's conclusion.