Question

Find the standard deviation of age of the persons from the following distribution of 125 persons living in a society. Also find the coefficient of standard deviation.

Age (years)	0 - 10	10 - 20	20 - 30	30 - 40	40 - 50	50 - 60	60 - 70	70 - 80
No. of persons	15	15	23	22	25	10	5	10

Answer 1

Mean:

x̄ = A + \(\frac{Σfd}{n}\) × c

= 35 + 2 / 125 × 100

= 35 + 20 / 125

= 35 + 0.16

= 35.16

Standard deviation of age: