Assignment:
I. A personnel manager at a large firm needs to estimate the mean length of stay, of its employees. She takes a random sample of employees and finds the sample mean (?x) to be 25 years.
a) Use the above data, x = 25, to find a 90% confidence interval for , if the employee sample size is 64, and a known population standard deviation = 16.
What is the appropriate distribution (z or t)?
b) What is its numerical value (obtain answer from the appropriate table, z or t?
c) What is the Confidence Interval? (Provide answer to at least two decimal places)
II. Find a 95% Confidence Interval for the mean length of stay of the employees of the large company if the point estimate for µ is x =25, the sample size is 9 and the sample standard deviation s = 12. (You can assume the distribution is normal).
a) What is the appropriate distribution (z or t)?
b) What is its numerical value (obtain answer from the appropriate table, z or t?
c) What is the Confidence Interval? (Provide answer to at least two decimal places.)