l. (30 marks) The samples are: 6, S, 11, 33, 4, 5, 60, 18, 35, 17, 23, 4, 14, ll, 9, 9, 8, 4, 20, 5, 21, 30, 48, 52,59, 43. (1) Please calculate the lower fourth, upper fourth and median. (12 marks) (2) Please plot the Stem-and-Leaf of samples (Indicate the units for stems and leaves). (4 marks) (3) Please calculate the sample mean. (4 marks) (4) Please judge whether the sample has outliers, extremes or not, if yes, please write down the outliers and extremes