Question

Find the mean of each of the following frequency distributions :

Class interval:	50-70	70-90	90-110	110-130	130-150	150-170
Frequency:	18	12	13	27	8	22

Answer 1

Let the assumed mean be A = 100 and h = 20.

We know that mean

Now we have

Putting the values in the above formula, we get

Hence, the mean is 112.20.