TimeTrends

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TimeTrends was developed to carry out statistical and trend analyses or equivalence tests by providing a series of linked procedures to:

• • Import data/time data easily

  • box and percentile plots

  • histograms  

  • display time trends with smoothing routines applied (Lowess,Gams)

  • statistical analysis by season (Seasonal Kendall test)

  • box and whisker plots by season with Kruskal-Wallis test

  • annual and seasonal event analysis

  • adjustment of data for flow variations (Lowess, Log-log, Gams)

  • Parametric trend analysis with equivalence testing of slope.

  • Equivalence testing of means

  • Non-parametric Kruskal-Wallis and Mann-Whitney, Wilcoxon signed rank.

  • Least absolute and quantile regression

  • determine trends through multivariate models (linear regression, generalised additive (GAM), or Loess).

  • False discovery rate

  • Handle censored data 

  • Piecewise regression

 The steps in a typical analysis are:

 ·        open file  of environmental data

·        plot variable against time and fit linear and smoothing functions

·        statistical Kendall analysis of trends with time and season

·        seasonal box plots and event analysis

·        multivariate analysis: regression,  GAMs or Loess

 Output

Data and results of analyses are shown on a series of pages with tabs.

 Most analyses will usually have both graphical and text outputs, with the results displayed on a graph page and text output on the results page.