Under this method, the Mean is computed directly from the given series by the application of the following models:

∑*FM*= Sum of the product of mid values and their frequencies.Where, ∑*FX*= Sum of the product of the values and their corresponding frequencies.

N = Sum of frequencies i.e. ∑ *F *or total number of observations

This method is advisable when the size of the values of a series are small and simple.