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 |
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 |
alternative | The usual notation for the alternate hypothesis. Default is |
printstat | Logical |
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
#> 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