Mean Deviation

Mean deviation measures how far, on average, each data point strays from a central value — typically the mean or the median. Unlike variance, which squares those distances, mean deviation treats every deviation with equal weight, making it more intuitive to interpret. It tells you the typical "spread" in the same units as the original data, so a mean deviation of 5 marks means scores are, on average, 5 marks away from the centre. This simplicity makes it a natu …