Any ancient tombs were cut from limestone rock that contained uranium. since most such tombs are not well-ventilated, they may contain radon gas. in one study, the radon levels in a sample of 12 tombs in a particular region were measured in becquerels per cubic meter left parenthesis bq divided by m cubed right parenthesis. for this data, assume that x overbarequals3 comma 440 bq divided by m cubed and sequals1 comma 226 bq divided by m cubed. use this information to estimate, with 95% confidence, the true mean level of radon exposure in tombs in the region. interpret the resulting interval.