A personnel manager at the large firm needs to determine the mean length of stay,? of its employees. She takes a random sample of employees and finds out the sample mean () to be 25 years. a) Employ the above data, = 25, to find out a 90% confidence interval for ? if the employee sample size is 64, and ? = 16. b) Determine the appropriate distribution (z or t)? c) What is the numerical value of (z or t)? d) What is the Confidence Interval? (Show equation with filled in numerical values. Calculate answer.) e) Interpret the meaning of Confidence Interval for the mean length of stay, m of employees in large firm? (Concise answer.)