HomeInternational Rice Research Notesvol. 26 no. 2 (2001)

A randomization test and software to compare ecological communities

W.j. Zhang | K.g. Schoenly

Discipline: Ecology, Agriculture



Some typical assumptions made in many statistical tests include (1) random sampling of individuals from the population of interest, (2) equal population standard deviations or means for two groups tested, and (3) normal distributions for index values within groups (Manly 1997). In community analyses, however, data usually have taxa as indices and samples or communities as groups to be tested, and complex relations exist among different taxa. These assumptions are generally not met. Randomization is an effective method for tests of a hypothesis with community data and has been used in rice community studies (Zhang and Schoenly 1999a).