The following tab

We will find the average age using step - deviation method, where A = Assumed mean and h = length of class interval.

Here, let A = 29.5 and h = 10

Since, the class intervals are inclusive type, we’ll first convert it into exclusive type by extending the class interval from both the ends.

We have got

A = 29.5, h = 10, Σf_i = 80 & Σf_iu_i = 43

∵ mean is given by

⇒

⇒

Thus, mean age is 34.88 years.