In a shop there are 150 balls of 5 kinds of different radius . The frequency distribution of their diameters are as follows :

Find the average diameter of the balls.

Explanation

Here , let 47 be the origin . Then , u=x-47 , where x=diameter in mm.
We at first prepare the following table :

`therefore baru=(sum uf)/(sum f)=(17)/(150)=0.11` (approx.)
`therefore ` If the average of diameters of `barx` , then `barx=baru+47=(0.11+47)` mm=47.11 mm (approx.)