Periodically, the county Water Department tests the drinking water of homeowners for contminants such as lead and copper. The lead and copper levels in water specimens collected in 1998 for a sample of 10 residents of a subdevelopement of the county are shown below. a) Construct a 99% confidence interval for the mean lead level in water specimans of the subdevelopment. << b) Construct a 99% confidence interval for the mean copper level in water specimans of the subdevelopment. <<.