Sen's slope - fume package different output than zyp or wq
On 22.03.2013 01:09, Abby Frazier wrote:
Hello, I am trying to decide which package to use to calculate the non-parametric Sen's Slope for identifying trends in rainfall data (determine the slope between all pairs of points and take the median of those slopes). I have found three packages that output Sen's: "zyp", "wq" and "fume". The outputs of "zyp.sen()" and "mannKen()" from the zyp and wq packages match, but the output from fume's "mkTrend" is different. I tried looking at the code from these three and I could not really understand what zyp and wq are doing differently. It seems like "fume" is the only package that calculates a corrected Mann Kendall p-value based on temporal autocorrelation, so I would like to use this package to calculate my p-values, but I am cautious because if the calculations for Sen's are incorrect, maybe the corrected p-value is not correct either? Please let me know if I should provide some examples - but the discrepancies seem to show up in any dataset I use. Thanks!
I'd start to discuss inaccuracies or errors you found with the package maintainer in in case your are still in doubt look into the source code. Best, Uwe Ligges
Abby [[alternative HTML version deleted]]
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