Radon exposure in Egyptian tombs. Many ancient Egyptian tombs were cut from limestone rock that contained uranium. Since most tombs are not well- ventilated, guards, tour guides, and visitors may be exposed to deadly radon gas. In Radiation Protection Dosimetry (Dec. 2010), a study of radon exposure in tombs in the Valley of Kings, Luxor, Egypt (recently opened for public tours), was conducted.

The radon levels—measured in becquerels per cubic meter (Bq/m3)—in the inner chambers of a sample of 12 tombs were determined. For this data, assume that x = 3,643 Bq>m3 and s = 1,187 Bq>m3. Use this information to estimate, with 95% confidence, the true mean level of radon exposure in tombs in the Valley of Kings.

Interpret the resulting interval.