Find the value of p, if the mean of the following distribution is 20 x: 15 17 19 20+p 23 f: 2 3 4 5p 6

note : the method should be of sigma fixi.

Mean = (sigma fixi)/ (sigma fi)

           ={ (2 X 15) + (3 X 17) + (4 X 19) + 5p(20 + p) + (6 X 23) } / (2 + 3 + 4 + 5p + 6) 

           = (295 + 100p + 5p²) / (15 + 5p)

           = (59 + 20p + p²) / (3 + p)

Bt, mean = 20 ( given)

Therefore , (59 + 20p + p²) / ( 3 + p) = 20

                   => 59 + 20p + p² = 60 + 20p

                   => p² = 1

                   => p =1