Find the mean deviation about the median of the following distribution:

Given: Data distribution

To find: the mean deviation about the median

Let us make a table of the given data and append other columns after calculations

Now, here N=20, which is even.

Here median,

Both these observations lie in cumulative frequency 13, for which corresponding observation is 12.

So the above table with more columns is as shown below,

Hence Mean Deviation becomes,

Therefore, the mean deviation about the median of the distribution is 1.25