La problemática del ajuste en la etapa de la calibración

  1. González González, Antonio Gustavo
  2. Sayago Gómez, Ana
  3. García Asuero, Agustín

ISSN: 1909-4841

Year of publication: 2006

Volume: 1

Issue: 1

Pages: 107-128

Type: Article

More publications in: Tumbaga


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.