Find the mean deviation about the mean for the data.

    \[4\]

,

    \[7\]

,

    \[8\]

,

    \[9\]

,

    \[10\]

,

    \[12\]

,

    \[13\]

,

    \[17\]

Find the mean deviation about the mean for the data.

    \[4\]

,

    \[7\]

,

    \[8\]

,

    \[9\]

,

    \[10\]

,

    \[12\]

,

    \[13\]

,

    \[17\]

Solution:-

Given data

    \[4\]

,

    \[7\]

,

    \[8\]

,

    \[9\]

,

    \[10\]

,

    \[12\]

,

    \[13\]

,

    \[17\]

To find mean deviation,  first we have to find mean

    \[(\overline{x})\]

    \[\overline{x}=\frac{1}{8}\sum\limits_{i=1}^{8}{{{x}_{i}}}=\frac{80}{8}=10\]

Determine the respective values of the deviations from mean,

i.e.,

    \[{{x}_{i}}-\overline{x}\]

are,

    \[10-4=6\]

,

    \[10-7=3\]

,

    \[10-8=2\]

,

    \[10-9=1\]

,

    \[10-10=0\]

,

    \[10-12=-2\]

,

    \[10-13=-3\]

,

    \[10-17=-7\]

The deviations are

    \[6,3,2,1,0,-2,-3,-7\]

Therefore, the absolute values of the deviations,

    \[6,3,2,1,0,2,3,7\]

Therefore,

    \[\sum\limits_{i=1}^{8}{\left| {{x}_{i}}-\overline{x} \right|}=24\]

We know that Mean deviation = sum of deviations/ number of observations

=

    \[24/8\]

=

    \[3\]

Hence, the mean deviation for the given data is

    \[3\]

.