Question

Mean deviation from the mean for the observation $-1,0,4$ is

• A. $\sqrt{\frac{14}{3}}$
• B. $\frac{2}{3}$
• C. $2$
• D. none of these

Answer 1

The correct option is C $2$

Given observations are $-1,0,4$
Mean $\overline{x}=\frac{-1+0+4}{3}=1$
Now, deviations of $x_i$ from mean are $|-1-1|,|0-1|,|4-1|$ i.e.2,1,3
Sum of deviations $\Sigma |x_1-\overline{x}|=2+1+3=6$
Mean deviation = $=\frac{1}{n}\Sigma |x_1-\overline{x}|=\frac{1}{3}\times 6=2$