Mean deviation of 5 observations from their mean 3 is 1.2, then coefficient of mean deviation is

If the mean of 10 observations is 50 and the sum of the squares of the deviations of the observations from the mean is 250, then the coefficient of variation of those observations is

If the mean of 10 observations is 50 and the sum of the squares of the deviations of the observations from the mean is 250 , such the coefficient of variation of those observations is

If the mean of 10 observation is 50 and the sum of the square of the deviations of observation from the mean is 250, then the coefficient of variation of these observation is

If the mean of 10 observation is 50 and the sum of the square of the deviations of observation from the mean is 250, then the coefficient of variation of these observation is

If mean deviation through median is 15 and median is 450, then coefficient of mean deviation is

If the sum of the deviations of 50 observations from 30 is 50, then the mean of these observations is

If the sum of the deviations of 50 observations from 30 is 50, then the mean of these observations is