Let us find the m

Observe, here the class intervals are unequal but continuous. So, in order to find mean we need to simply find midpoints of the class intervals and further find f_ix_i.

We can solve this using three methods,

- Direct method

- Assumed-mean method

- Step Deviation method

We shall calculate the mean using direct method.

So, we have

∑f_ix_i = 748

∑f_i = 64

From direct method, mean is given by

Using the above values,

⇒ Mean = 11.69

Thus, mean is 11.69.