A U.S. dime weighs 2.268 grams when minted. A random sample of 15 circulated dimes showed a mean weight of 2.256 grams with a standard deviation of .026 grams. (a) Using α = .05, is the mean weight of...

A U.S. dime weighs 2.268 grams when minted. A random sample of 15 circulated dimes showed a mean weight of 2.256 grams with a standard deviation of .026 grams. (a) Using α = .05, is the mean weight of all circulated dimes lower than the mint weight? State your hypotheses and decision rule. (b) Why might circulated dimes weigh less than the mint specification?