The EPA considers indoor radon levels above 4 picocuries per liter (pCi/L) of air to be high enough to warrant amelioration efforts. Testsin a sample of 200 homes in a certain county found 127 (53.5%) of these sampled households to have indoor radon levels above 4 pCi / L. Compute the 95% condence interval of the proportion of all the households in the county that don't meet the EPA guidelines