La problemática del ajuste en la etapa de la calibración
- González González, Antonio Gustavo
- Sayago Gómez, Ana
- García Asuero, Agustín
ISSN: 1909-4841
Any de publicació: 2006
Volum: 1
Número: 1
Pàgines: 107-128
Tipus: Article
Altres publicacions en: Tumbaga
Resum
The factors, which exert an influence over the calibration process in chemical analysis, are subject of consideration. The postulates in which the least squares method are based; the goodness-of-fit of the model and the residual analysis are subject of study. This last topic is a powerful tool, which allows checking the assumptions assumed, as well as taking decisions concerning data independence or homogeneity (homocedasticity). When the variance is non-uniform (heterocedasticity), data are either weighted or a transformation is carried out. The strategies to be applied in more complex cases such as non-linear calibration curves with non-uniform variance are also analysed. Finally, the use of rational or spline functions are considered.