Trendanalysen mit Mann-Kendall-Test und Theil-Schätzer. Teil 2: Gewichtung der Daten
Helm, Dieter
Umweltwissenschaften und Schadstoff-Forschung 19 (2007), 4, 240-242
Abstract
Goal and Scope
An extension for trend analysis with Mann Kendall test and Theil estimator is presented which enables the weighting of data by weight factors.
Methods
It is shown in which way the weighting can effect the outcome of a trend analysis. Weighting is done in relation to the different sample sizes of the data points. A value or an observation derived from many specimens will be considered more reliable than a value derived from only a few specimens and will thus get a higher weighting factor.
Results
When weighting is applied, this will effect the Theil estimator rather than the Mann Kendall test. As a result the regression line is tilted towards those points with higher weights.
Outlook
Future must show whether the extensions presented here and in part 1 prove to be practical for the trend analysis in environmental monitoring or not.