Performs a nonparametric Wilcoxon signed-rank test of whether the median difference between two columns of paired censored data equals 0. Uses the Pratt adjustment for pairs of equal or indistinguishable values.

`cen_signedranktest(xd, xc, yd, yc, alternative = "two.sided", printstat = TRUE)`

- xd
The first column of data values plus detection limits

- xc
The column of censoring indicators for

`xd`

, where 1 (or`TRUE`

) indicates a detection limit in the xd column, and 0 (or`FALSE`

) indicates a detected value in xd.- yd
The second column of data values plus detection limits, or a single number representing a standard / guideline value.

- yc
The column of censoring indicators for yd, where 1 (or

`TRUE`

) indicates a detection limit in the yd column, and 0 (or`FALSE`

) indicates a detected value in`yd`

. Not needed if`yd`

is a single standard number.- alternative
The usual notation for the alternate hypothesis. Default is

`“two.sided”`

. Options are`“greater”`

or`“less”`

.- printstat
Logical

`TRUE`

/`FALSE`

option of whether to print the resulting statistics in the console window, or not. Default is`TRUE.`

Prints a list of Wilcoxon Signed-Rank test with Pratt correction for ties statistics containing the following components:

`n`

Number of samples`Z`

The value of the test statistic`p.value`

the p-value of the test

Helsel, D.R., 2011. Statistics for censored environmental data using Minitab and R, 2nd ed. John Wiley & Sons, USA, N.J.

Page, E.B., 1963. Ordered Hypotheses for Multiple Treatments: A Significance Test for Linear Ranks. Journal of the American Statistical Association 58, 216–230. doi: 10.2307/2282965

Pratt, J.W., 1959. Remarks on Zeros and Ties in the Wilcoxon Signed Rank Procedures. Journal of the American Statistical Association 54, 655–667. doi: 10.2307/2282543

```
data(atrazine)
cen_signedranktest(atrazine$June,atrazine$JuneCen,atrazine$Sept,atrazine$SeptCen)
#> Censored signed-rank test for (x:atrazine$June - y:atrazine$Sept) equals 0
#> alternative hypothesis: true difference atrazine$June - atrazine$Sept does not equal 0
#>
#> Pratt correction for ties
#> n = 24, Z = -3.319, p.value = 0.0009033
```