Radiation in Baby Teeth Listed below are amounts of strontium-90 (in millibecquerels, or mBq, per gram of calcium) in a simple random sample of baby teeth obtained from Pennsylvania residents and New York residents born after 1979 (based on data from “An Unexpected Rise in Strontium-90 in U.S. Deciduous Teeth in the 1990s,” by Mangano et al., Science of the Total Environment, Vol. 317).

a. Use a 0.05 significance level to test the claim that the mean amount of strontium-90 from Pennsylvania residents is greater than the mean amount from New York residents.

b. Construct a confidence interval for testing the claim in part (a).

Pennsylvania: 155 142 149 130 151 163 151 142 156 133 138 161 New York: 133 140 142 131 134 129 128 140 140 140 137 143