The variance and mean of 15 observations are respectively 6 and 10 . If each observation is increased by 8 then the new variance and new mean of resulting observations are respectively

For the set of 50 observations, the sum of their squares is 3050 , their arithmetic mean is 6. Hence the standard deviation of these observations is

The arithmetic mean of marks in Mathematics for four divisions A, B, C and D were $$80,75,70$$ and 72 respectively. Their standard deviations were $$12,6,8$$ and 10 respectively. Then, division ______ has more uniformity.

If the standard deviation of data is 12 and mean is 72, then coefficient of variation is