[R-sig-eco] Multiply censored observations

[is@beii@ m@iii@g oii gheme@t@c@]

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 Hi everyone, 
 I am working on a project where I need to conduct non-seasonal and
seasonal trend tests of multiply censored data (i.e., data with
multiple detection 
 limits). 
 An old thread on this mailing list
(http://r-sig-ecology.471788.n2.nabble.com/Seasonal-Mann-Kendall-with-multiple-detection-limits-td7578991.html
[1]) 
 suggests that it is possible to perform these types of trend tests in
R using functions from USGS packages: 
        1.  USGSwsQW package has a function called kendallATS.test
that performs a non-seasonal Mann-Kendall trend test;
        2.  restrend package has a function called censSeaken that
performs a seasonal Kendall trend test. 
 Now, I looked for the USGSwsQW package and couldn't find it. 
Instead, I found the USGS package smwrQW
(https://rdrr.io/github/USGS-R/smwrQW/), [2] which 
 includes the function kendallATS.test.  The restrend package I could
find and it does include the censSeaken function. 
 The syntax of the kendallATS.test function is kendallATS.test(x, y,
na.rm = TRUE), where in my case x will stand for year and y will be a
concentration 
 subjected to multiple detection limits.  According to the help file,
y needs to be 'any data that can be converted to a left-censored data
object'. 
 The USGS packages seem to have an as.lcens() function which would
enable me to specify y as a left-censored vector of concentration
values subjected to 
 a single censoring limit.  But they also have an as.mcens() function
which would accept multiple censoring/detection limits.  
 Initially, I thought that kendallATS.test would accept both lcens and
mcens data values.  But it only accepts lcens data values, so I am not
sure 
 whether we are supposed to somehow convert mcens to lcens data values
prior to feeding them to kendallATS.test?  If we are supposed to do
this 
 conversion, I am also not sure how the conversion should work as far
as as.lcens is concerned. 
 As an example, if y consists of the values "

Links:
------
[1]
http://r-sig-ecology.471788.n2.nabble.com/Seasonal-Mann-Kendall-with-multiple-detection-limits-td7578991.html
[2] https://rdrr.io/github/USGS-R/smwrQW/),
[3] mailto:isabella using ghement.ca
[4] http://sitemail.wvthosting.com/<a href=

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