Articles | Volume 16, issue 4
Hydrol. Earth Syst. Sci., 16, 1255–1257, 2012
https://doi.org/10.5194/hess-16-1255-2012
Hydrol. Earth Syst. Sci., 16, 1255–1257, 2012
https://doi.org/10.5194/hess-16-1255-2012

Technical note 26 Apr 2012

Technical note | 26 Apr 2012

Technical note: A significance test for data-sparse zones in scatter plots

V. V. Vetrova and W. E. Bardsley V. V. Vetrova and W. E. Bardsley
  • Department of Earth & Ocean Sciences, University of Waikato, Hamilton, New Zealand

Abstract. Data-sparse zones in scatter plots of hydrological variables can be of interest in various contexts. For example, a well-defined data-sparse zone may indicate inhibition of one variable by another. It is of interest therefore to determine whether data-sparse regions in scatter plots are of sufficient extent to be beyond random chance. We consider the specific situation of data-sparse regions defined by a linear internal boundary within a scatter plot defined over a rectangular region. An Excel VBA macro is provided for carrying out a randomisation-based significance test of the data-sparse region, taking into account both the within-region number of data points and the extent of the region. Example applications are given with respect to a rainfall time series from Israel and also to validation scatter plots from a seasonal forecasting model for lake inflows in New Zealand.

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