Question: Copper Thieves As a result of increasing commodity prices, the theft of certain metals has increased dramatically. Because copper is used in so many items and is difficult to trace, thieves across the United States have become more brazen. A major target for thieves has been copper wiring in electrical power substations and utility poles. The leading states for thefts are Ohio, Texas, and Georgia.2 Independent random samples of copper theft reports were obtained from two states, and the estimated dollar amount was recorded for each. The summary statistics and known variances are given in the following table.
a. Assume the underlying distributions are normal and find a 95% confidence interval for the true difference in population mean amounts stolen.
b. Use the confidence interval to determine whether there is any evidence that the mean dollar amount of copper stolen differs for the two states.