NIOSHTIC-2 Publications Search
Frequency distributions from birth, death and creation processes.
Bartley-DL; Ogden-T; Song-R
Biosystems 2002 Aug; 66(3):179-191
The time-dependent frequency distribution of groups of individuals versus group size was investigated within a continuum approximation, assuming a simplified individual growth, death and creation model. The analogy of the system to a physical fluid exhibiting both convection and diffusion was exploited in obtaining various solutions to the distribution equation. A general solution was approximated through the application of a Green's function. More specific exact solutions were also found to be useful. The solutions were continually checked against the continuum approximation through extensive simulation of the discrete system. Over limited ranges of group size, the frequency distributions were shown to closely exhibit a power-law dependence on group size, as found in many realizations of this type of system, ranging from colonies of mutated bacteria to the distribution of surnames in a given population. As an example, the modeled distributions were successfully fit to the distribution of surnames in several countries by adjusting the parameters specifying growth, death and creation rates.
Models; Group-dynamics; Families; Data-processing; Statistical-analysis; Statistical-quality-control
National Institute for Occupational Safety and Health, 4676 Columbia Parkway, Cincinnati, OH 45226, USA
Issue of Publication
Page last reviewed: April 12, 2019
Content source: National Institute for Occupational Safety and Health Education and Information Division