# ISS (Statistical Services) Statistics Paper IV: Questions 1 of 92

Appeared in Year: 2015

Essay Question▾

### Describe in Detail

Explain stationary and stable population. State the situation when the age distribution of two stable populations would be identical.

## Explanation

Stationary Population: If the size of a population is constant and its composition according to age and sex also remains constant over time, then such a population is known as stationary population. The constancy in population for size and composition is maintained if,

1. Births and deaths are equal in number and are uniformly distributed over the year.

2. Either there is no migration or the emigration and immigration are equal during the year.

Stable Population: If a population increases (decreases) at a constant rate, that is the rates of births and deaths remain constant, the population is said to stable. Further a stable population holds following properties:

1. It has a fixed age and sex distribution over time.

2. Population is closed for migration either way.