Find the mean of the following frequency distribution: Classes:               0-20         20-40                            40-60       60-80                            80-100 Frequency:          15            18                            21            29                            17

Explanation

`x_i = 10, 30, 50, 70, 90`

`f_i = 15 , 18 , 21, 29, 17`

`A= 50, L=20`

`d_i= -40, -20, 0 , 20, 40`

`u_i= (d_i-h)= -2, -1, 0 , 1 ,2`

`f_i*u_i= -30, -18, 0 ,29, 34 `

`sum(f_i*u_i) = 15`

`sumf_i = N= 100`

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