(1) Co-efficient of variation of two series are 50% and 69%. Their standard deviations are 21.2 and 15.6 respectively. What are their arithmetic means? (i) Mean of 100 items is 58 and their standard...

(1) Co-efficient of variation of two series are 50% and 69%. Their standard deviations are 21.2 and 15.6 respectively. What are their arithmetic means? (i) Mean of 100 items is 58 and their standard deviation is 4. Find the sum of squares of all items.