Calculate the mean deviation about median from the following data: 340, 150, 210, 240, 300, 310, 320.

Explanation

`{(CI, x_i ,f_i ,c.f ,x_i-M ,f_i(x_i-M)),(0-10,5,6,6,23,138),(10-20,15,7,13,13,91),(20-30,25,15,28,3,45),(30-40,35,16,44,7,112),(40-50,45,4,48,17,68),(50-60,55,2,50,27,54),(0,0,sumf_i=100,0,0,sumf_i(x_i-M)=508):}`
hence
Now
N= `sumf_i =50,` Median `= N/(2) = 25` term
so above c.f of class` 20-30` is 28 which is slightly greater than 25 , so median class `20-30`

`Median = l + ((N/2)-c)/(f) xx h` ,
`= 20+ ((50/2)-13)/(15) xx 10 = 28`
now
Mean deviation (M) = `(sumf_i(x_i-M))/(f_i) = (508)/(50) = 10.16`