Question

Question 8 Find the mean deviation about the median for the data

xi 15 21 27 30 35

fi 3 5 6 7 8

Class X1 - Maths -Statistics Page 360

Answer 1

we have to find out mean deviation about Median , so first of all we have to find out Median and then we have to calculate mean deviation about Median by using formula ,
= ∑fᵢ(xᵢ - M)/∑fᵢ

see attachment ,
here,
N =.∑fᵢ = 29 ( an odd number )
so, Median (M) = {( N + 1)/2 }th observation
= {(29 + 1)/2}th observation
= 15th observation
= 30
$\therefore\:Mean\: deviation\: about\: Median=\frac{\sum{f_i | (x_i-M)| }}{\sum{f_i}}\\\\=\frac{148}{29}\\\\=5.1$