Question

Find the mean deviation about the median of the following frequency distribution: Class:, 0-6, 6-12, 12-18, 18-24, 24-30 Frequency:, 8, 10, 12, 9, 5

Answer 1

`x_i = 3, 9, 15, 21, 27`
`f = 8, 10,12, 9,5 `
`cf = 8, 18 , 30, 39, 44`
`N= sumfi = 44`
`N/2 = 22`
`median class = 12 to 18 `
`l= 12 , F=18 , f=12, h=6 `
`median= l + (n/2 -F)/f *h= 12+ (22-18)/12*6 = 14`
now, again in table
`d_i = |x_i-14| = 1, 5, 1, 7 , 13`
`f_i*d_i = 88, 50, 12, 63 , 65`
`sum(fi*di) = 278`
mean deviation about median is` (sum(f_i*d_i))/N`
`278/44 = 6.318`