premise: The worlds population is determined by the balance between the birth rate and the death rate. The population of a particular area can also increase or decrease due to migration. It will increase when the number of immigrants exceeds the number of emigrants and decrease when the number of emigrants exceeds the number of immigrants. The make-up of a population by its age and sex and its life-expectancy will also have implications for the population size and its expected future growth or decline.
hypothesis: A higher birth rate will mean a growing world population.