cen_signedranktest: Wilcoxcon Signed-Rank test for censored data

In NADA2: Data Analysis for Censored Environmental Data

Wilcoxcon Signed-Rank test for censored data

Description

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.

Usage

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

Arguments

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.

Value

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

References

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. \Sexpr[results=rd]{tools:::Rd_expr_doi("https://doi.org/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. \Sexpr[results=rd]{tools:::Rd_expr_doi("https://doi.org/10.2307/2282543")}

Examples

data(atrazine)

cen_signedranktest(atrazine$June,atrazine$JuneCen,atrazine$Sept,atrazine$SeptCen)

NADA2 documentation built on Sept. 11, 2024, 8:06 p.m.