A city near a government weapons clean-up site is concerned about the level of radioactive byproducts in their water supply. The EPA limit on naturally occurring radiation is 5 picocuries per liter of water. A random sample of 26 water specimens from the city water supply gives y = 4.82 and s = 0.79. Does this provide sufficient evidence that the water supply is safe (i.e., below the maximum level allowed)? Test, using a = 0.01, and explain what your results mean.