Model-independent procedure for area estimation and intergroup comparisons.

A method is provided for estimating the area under a response-time curve for an experimental situation where independent observations are made at each time point. The procedure utilizes least-squares spline functions and the jackknife technique to provide area estimates, standard errors, and a statistical test for intergroup comparisons. The method is based on an empirical model and provides a means of analysis when no prior model can be specified or if the incorrect specification of a model will produce invalid results. The method is illustrated using data from a study comparing the pharmacokinetic behavior of a fasciolicide in rats having either a young or old parasitic infestation. The results obtained are comparable with those generated by a model-dependent approach.