2. The table below shows the time taken lav students to prepare for examinations. Time min Fre nuenc l l - 20 3 21-30 7" 3140 12 4150 5160 61?0 TI- 80 a. Calculate the: i, mean time ii. mean Deviation iii. variance and standard deviation iv. Coefcient of Variation b. Use the information to create a: i, Frequency.r Polygon ii. Histogram iii. Cumulative Frequency Curve c. Use the Cumulative Frequencv Curve to estimate the: i, Median ii. Lower and Upper Quartile