How do I solve this problem . Please show step by step. I'm having a hard time with the formula.
Periodically, a town water department tests the the drinking water of homeowners for contaminants such as lead. The lead levels in water specimens collected for a sample of 10 residents of the town had a mean of 2.4 mg/L and a standard deviation of 1.3 mg/L. Complete parts a through c.
a. Construct a 95% confidence interval for the mean lead level in water specimens from the town.