[Rd] Inconsistencies in wilcox.test
Karolis Koncevičius
k@ro||@@koncev|c|u@ @end|ng |rom gm@||@com
Sat Dec 7 19:55:36 CET 2019
Hello,
Writing to share some things I've found about wilcox.test() that seem a
a bit inconsistent.
1. Inf values are not removed if paired=TRUE
# returns different results (Inf is removed):
wilcox.test(c(1,2,3,4), c(0,9,8,7))
wilcox.test(c(1,2,3,4), c(0,9,8,Inf))
# returns the same result (Inf is left as value with highest rank):
wilcox.test(c(1,2,3,4), c(0,9,8,7), paired=TRUE)
wilcox.test(c(1,2,3,4), c(0,9,8,Inf), paired=TRUE)
2. tolerance issues with paired=TRUE.
wilcox.test(c(4, 3, 2), c(3, 2, 1), paired=TRUE)
# ...
# Warning: cannot compute exact p-value with ties
wilcox.test(c(0.4,0.3,0.2), c(0.3,0.2,0.1), paired=TRUE)
# ...
# no warning
3. Always 'x observations are missing' when paired=TRUE
wilcox.test(c(1,2), c(NA_integer_,NA_integer_), paired=TRUE)
# ...
# Error: not enough (finite) 'x' observations
4. No indication if normal approximation was used:
# different numbers, but same "method" name
wilcox.test(rnorm(10), exact=FALSE, correct=FALSE)
wilcox.test(rnorm(10), exact=TRUE, correct=FALSE)
From all of these I am pretty sure the 1st one is likely unintended,
so attaching a small patch to adjust it. Can also try patching others if
consensus is reached that the behavioiur has to be modified.
Kind regards,
Karolis Koncevičius.
---
Index: wilcox.test.R
===================================================================
--- wilcox.test.R (revision 77540)
+++ wilcox.test.R (working copy)
@@ -42,7 +42,7 @@
if(paired) {
if(length(x) != length(y))
stop("'x' and 'y' must have the same length")
- OK <- complete.cases(x, y)
+ OK <- is.finite(x) & is.finite(y)
x <- x[OK] - y[OK]
y <- NULL
}
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