# A variable x takes values 1,2,3,4,5 with corresponding frequencies 1,2,3,4,5. Then the mean deviation of x from mean?

Mean deviation of x from mean is [∑ |xi$\dpi{100} \mu$|.fi] / [∑ fi ], where $\dpi{100} \mu$ is mean, f is frequency.
Now, mean, $\dpi{100} \mu$ = ∑ xifi / ∑ fi  =  (1.1 + 2.2 + 3.3 + 4.4 + 5.5) / (1 + 2 + 3 + 4 + 5) = 55/15 = 11/3.
∑ |xi$\dpi{100} \mu$|.fi = |1 – 11/3|.1 + |2 – 11/3|.2 + |3 – 11/3|.3 + |4 – 11/3|.4 + |5 – 11/3|.5
$\dpi{100} \therefore$ [∑ |xi$\dpi{100} \mu$| fi] / [∑ fi ] = 16 / 15 = mean deviation of x from mean.