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2. ### Population density - Wikipedia

en.wikipedia.org/wiki/Population_density

Population density (in agriculture: standing stock or plant density) is a measurement of population per unit land area. It is mostly applied to humans, but sometimes to other living organisms too. It is a key geographical term. [1] In simple terms, population density refers to the number of people living in an area per square kilometre or other ...

3. ### Statistics - Wikipedia

en.wikipedia.org/wiki/Statistics

Statistics is a mathematical body of science that pertains to the collection, analysis, interpretation or explanation, and presentation of data, [9] or as a branch of mathematics. [10] Some consider statistics to be a distinct mathematical science rather than a branch of mathematics. While many scientific investigations make use of data ...

4. ### Population balance equation - Wikipedia

en.wikipedia.org/wiki/Population_balance_equation

Population balance equations (PBEs) have been introduced in several branches of modern science, mainly in Chemical Engineering, [1] to describe the evolution of a population of particles. This includes topics like crystallization, [2] leaching (metallurgy), [3] [4] liquid–liquid extraction, gas-liquid dispersions like water electrolysis, [5 ...

5. ### Lotka–Volterra equations - Wikipedia

en.wikipedia.org/wiki/Lotka–Volterra_equations

The Lotka–Volterra equations, also known as the Lotka–Volterra predator–prey model, are a pair of first-order nonlinear differential equations, frequently used to describe the dynamics of biological systems in which two species interact, one as a predator and the other as prey. The populations change through time according to the pair of ...

6. ### Population dynamics - Wikipedia

en.wikipedia.org/wiki/Population_dynamics

Population dynamics is the type of mathematics used to model and study the size and age composition of populations as dynamical systems. History [ edit ] Population dynamics has traditionally been the dominant branch of mathematical biology , which has a history of more than 220 years, [1] although over the last century the scope of ...

7. ### Number density - Wikipedia

en.wikipedia.org/wiki/Number_density

Number density. The number density (symbol: n or ρN) is an intensive quantity used to describe the degree of concentration of countable objects ( particles, molecules, phonons, cells, galaxies, etc.) in physical space: three-dimensional volumetric number density, two-dimensional areal number density, or one-dimensional linear number density.