The EPA considers indoor radon levels above 4 picocuries per liter (pCi/L) of air to be high enough to warrant amelioration efforts. Tests in a sample of 200 Centre County Pennsylvania homes found 127...

The EPA considers indoor radon levels above 4 picocuries per liter (pCi/L) of air to be high enough to warrant amelioration efforts. Tests in a sample of 200 Centre County Pennsylvania homes found 127 of these sampled households to have indoor radon levels above 4 pCi/L. Using a 96% confidence level estimate the proportion of all Centre County Pennsylvania homes having the indoor radon level above 4pCi/L. Finally give a confidence statement.