1. The personnel manager of a firm with 200 employees wants to examine the health benefit

claims over the past year. The claims' standard deviation is known to be $80. The manager

selects 40 employees and find that the average amount claimed during the year was $260.

Construct and interpret the 95% confidence interval for the population mean. Was it

necessary to make any assumptions about the shape of the population distribution? Explain.

Need graph and step by step