Question

Find the mean:

Class interval:	0-10	10-20	20-30	30-40	40-50
Frequency:	9	12	15	10	14

Answer 1

Let’s consider the assumed mean (A) = 25

From the table it’s seen that,

A = 25 and h = 10

Mean = A + h x (\(\frac{Σf_i u_i}{N}\))

= 25 + 10 x (\(\frac{8}{60}\))

= 25 + \(\frac{4}{3}\)

= \(\frac{79}{3}\)

= 26.333