1. curvilinear correlation any correlation in which the rates of change of the variables is not constant
2. nonlinear correlation any correlation in which the rates of change of the variables is not constant
3. curvilinear regression the relation between variables when the regression equation is nonlinear (quadratic or higher order)
4. fourfold point correlation an index of the relation between any two sets of scores that can both be represented on ordered binary dimensions (e.g., male-female)
5. partial correlation a correlation between two variables when the effects of one or more related variables are removed
6. Kendall rank correlation a nonparametric measure of the agreement between two rankings
7. coefficient of correlation a statistic representing how closely two variables co-vary
8. first-order correlation a partial correlation in which the effects of only one variable are removed (held constant)
9. partner relation the responsibility of partners to act in one another's best interests
10. phylogenetic relation (biology) state of relationship between organisms or groups of organisms resulting in resemblance in structure or structural parts
11. negative correlation a correlation in which large values of one variable are associated with small values of the other; the correlation coefficient is between 0 and -1
12. rank-order correlation the most commonly used method of computing a correlation coefficient between the ranks of scores on two variables
13. rank-difference correlation the most commonly used method of computing a correlation coefficient between the ranks of scores on two variables
14. biserial correlation a correlation coefficient in which one variable is many-valued and the other is dichotomous
15. direct correlation a correlation in which large values of one variable are associated with large values of the other and small with small; the correlation coefficient is between 0 and +1
16. anaphoric relation the relation between an anaphor and its antecedent
17. conservator-ward relation the responsibility of a conservator to act in the best interests of the ward
18. chance-half correlation a correlation coefficient calculated between scores on two halves of a test; taken as an indication of the reliability of the test
19. tau coefficient of correlation a nonparametric measure of the agreement between two rankings
20. rectilinear regression the relation between variables when the regression equation is linear: e.g., y = ax + b