We first, find the class mark `x_(i)` of each class and then proceed as follows.
`therefore "Assumed mean",a=110`
Class width, h=4
and total observation, N=100
By assuming mean method, `"Mean" bar(x)=(sumf_(i)x_(i))/(sumf_(i))`
`=110+(-8)/(100)=110-0.08=109.92`