[Rd] propogation of rounding error for t.tests with unequal sample sizes (PR#7225)

From: <tucker_at_mpi.com>
Date: Tue 14 Sep 2004 - 04:57:42 EST

# users would benefit from a warning about the behavior in the
# groups.unbalanced case below. A propogation of difference is the variance
# calculation is leading to an apparently significant difference in
# means, even though the numeric values are all identical. Obviously upon
# inspection the difference in means is meaningless, but users might be warned
# if all of the input data is identical

xx <- rep(2.10,80)

groups.balanced <- as.factor(c(rep("one",40),rep("two",40))) groups.unbalanced <- as.factor(c(rep("one",44),rep("two",36)))

t.test(xx ~ groups.balanced)

t.test(xx ~ groups.unbalanced)

<<insert bug report here>>

--please do not edit the information below--

Version:
 platform = sparc-sun-solaris2.8
 arch = sparc
 os = solaris2.8
 system = sparc, solaris2.8
 status =
 major = 1
 minor = 9.0
 year = 2004
 month = 04
 day = 12
 language = R

Search Path:
 .GlobalEnv, package:methods, package:stats, package:graphics, package:utils, Autoloads, package:base

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https://stat.ethz.ch/mailman/listinfo/r-devel Received on Tue Sep 14 05:01:13 2004

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