The development and existence of the organism as an integral whole is dependent on correlation. In biology, the interdependence of the structure and functions of the cells, tissues, organs, and systems of the body, manifested in the body’s development and in its life activities. See also REGRESSION, CAUSAL MODELLING, PATH ANALYSIS. It also must be remembered that the apparent association may be caused by a third factor influencing both variables systematically For situations in which three or more variables are involved, techniques of MULTIVARIATE ANALYSIS exist. Spurious relationships can be found between variables so there has to be other evidence to support the inference of one variable influencing the other.
The technique of correlation analysis is mainly used on interval level data (see CRITERIA AND LEVELS OF MEASUREMENT), but tests also exist for other levels of data (see SPEARMAN RANK CORRELATION COEFFICIENT).įinding a correlation does not imply causation. When no association is found between variables they are said to have statistical independence. Curvilinear correlation occurs when the variation of the variables is nonlinear, the rate of change of one being faster than the other. Correlation coefficients are constructed essentially as measures of departure from this straight line. When presented graphically, for a perfect relationship between variables a straight line can be drawn through all points on the graph. a relationship in which the variation in one variable is directly proportional to the variation in the other). Most of these focus on a linear relationship (i.e. Negative correlation describes the situation in which the variables vary inversely, one increasing when the other decreases.Ĭorrelation can be measured by a statistic, the CORRELATION COEFFICIENT or coefficient of association, of which there exist several forms. Positive correlation describes the situation in which, if one variable increases, so also does the other. correlation the association between two VARIABLES such that when one changes in magnitude the other one does also, i.e. McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
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