Solution:-

Draw a table of the given data and append other columns after calculations.

We know that, N = \[26\], which is even.

So, median is the mean of the \[13\]and \[14\] observations. Both of these observations lie in the cumulative frequency \[14\], for which the corresponding observation is \[7\].

Then,

Median = (\[13\] observation + \[14\] observation)/2

= \[(7+7)/2\]

= \[14/2\]

= \[7\]

Therefore, \[\sum\limits_{i=1}^{6}{{{f}_{i}}}=26\]and \[\sum\limits_{i=1}^{6}{{{f}_{i}}}\left| {{x}_{i}}-M \right|=84\]

Mean deviation(M) =\[\frac{1}{N}\sum\limits_{i=1}^{6}{{{f}_{i}}}\left| {{x}_{i}}-M \right|\]

=\[(1/26)\times 84\]

=\[3.23\]

Therefore, the mean deviation about the median is \[3.23\]