title: Statistical analysis of structure-activity relationships.
abstract: The relationship between organic structure and biological activity (toxicity) is examined by statistically comparing concentration-response regression lines among structurally related compounds. Response data from acute toxicity tests are initially transformed to the logistic function while concentration data are transformed to the logarithm base 10 before being fit to a linear model using a weighted least squares analysis. A sequential approach is presented that uses statistical models for testing differences among related compounds. The approach first tests for the overall equality of regression lines (slopes and intercepts). If the regression lines are found to be different, another set of tests are conducted to determine if the slopes of the lines are equal (i.e. parallel). If the slopes are equal, multiple comparisons are made using Scheffé's procedure for determining which compounds differ in their intercepts. Relative toxicities are then estimated for various concentrations of particular compounds.
mesh_terms: D012044:Regression Analysis; D013223:Statistics as Topic; D013329:Structure-Activity Relationship; D014116:Toxicology