Question

The Mean deviation about A.M. of the numbers $3,4,5,6,7$ is :

• A. $25$
• B. $5$
• C. $1.2$
• D. $0$

Answer 1

The correct option is C $1.2$

Mean deviation is defined as the average of the absolute deviation of the observations from their mean.
Here, the arithmetic mean of the given observations is $\frac{3+4+5+6+7}{5}=5$
Thus, mean deviation = $\frac{|3-5|+|4-5|+|5-5|+|6-5|+|7-5|}{5}=\frac{6}{5}=1.2$
Hence, option 'C' is correct.