Explain HDI, Life Expectancy at birth, Gross Enrolment Ratio and per Capita Income.

These terms are explained as given below:
(a) HDI stands for Human Development Index. HDI ranks in the world arc for 177 countries in all.
(b) Life expectancy at birth denotes, as the name suggests, average expected length of life of a person at the time of birth.
(c) Gross Enrolment Ratio for three levels means enrolment ratio for primary school, secondary school and higher education beyond secondary school.
(d) Per Capita Income is calculated in dollars for all countries so that it can be compared. It is also done in a way so that every dollar would buy the same amount of goods and services in any country.