• 1) A company manufactures batteries for watches. A random sample of 144 batteries is taken and the sample mean life is 5.5 years with a standard deviation of 0.6 years. If you were constructing a 99% two-sided confidence interval estimate, the lower limit would be:
• 2- A company wishes to determine if the average salary of its clerks is really $340. The company researcher takes a sample of 64 clerks and finds that X =$300 and s = $80.
• a)Test at = 0.05.
• b)Constructa95%CIEof
• with solution.thank you.