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authorranke <ranke@5fad18fb-23f0-0310-ab10-e59a3bee62b4>2006-06-23 15:33:27 +0000
committerranke <ranke@5fad18fb-23f0-0310-ab10-e59a3bee62b4>2006-06-23 15:33:27 +0000
commit9e0dae397df8c18e7333d2604cae96b2a7927420 (patch)
treeb513b791985426bab6c18850d2f8c308c411c1a5 /man/lod.Rd
parentfb7ea47c774f67b8c26a6844f4ade8935a8653cc (diff)
- inverse.predict now has a var.s argument instead of the never
tested ss argument. This is documented in the updated vignette - loq() now has w.loq and var.loq arguments, and stops with a message if neither are specified and the model has weights. - calplot doesn't stop any more for weighted regression models, but only refrains from drawing prediction bands - Added method = "din" to lod(), now that I actually have it (DIN 32645) and was able to see which approximation is used therein. - removed the demos, as the examples and tests are already partially duplicated - The vignette is more of a collection of various notes, but should certainly be helpful for the user. - Version bump to 0.1-xxx git-svn-id: http://kriemhild.uft.uni-bremen.de/svn/chemCal@16 5fad18fb-23f0-0310-ab10-e59a3bee62b4
Diffstat (limited to 'man/lod.Rd')
-rw-r--r--man/lod.Rd20
1 files changed, 14 insertions, 6 deletions
diff --git a/man/lod.Rd b/man/lod.Rd
index c2fe4e9..055074c 100644
--- a/man/lod.Rd
+++ b/man/lod.Rd
@@ -5,7 +5,7 @@
\alias{lod.default}
\title{Estimate a limit of detection (LOD)}
\usage{
- lod(object, \dots, alpha = 0.05, beta = 0.05)
+ lod(object, \dots, alpha = 0.05, beta = 0.05, method = "default")
}
\arguments{
\item{object}{
@@ -24,10 +24,18 @@
\item{beta}{
The error tolerance beta for the detection limit.
}
+ \item{method}{
+ The default method uses a prediction interval at the LOD
+ for the estimation of the LOD, which obviously requires
+ iteration. This is described for example in Massart, p. 432 ff.
+ The \dQuote{din} method uses the prediction interval at
+ x = 0 as an approximation.
+ }
}
\value{
A list containig the corresponding x and y values of the estimated limit of
- detection of a model used for calibration. }
+ detection of a model used for calibration.
+}
\description{
The decision limit (German: Nachweisgrenze) is defined as the signal or
analyte concentration that is significantly different from the blank signal
@@ -39,7 +47,7 @@
one-sided significance test).
}
\note{
- - The default values for alpha and beta are recommended by IUPAC.
+ - The default values for alpha and beta are the ones recommended by IUPAC.
- The estimation of the LOD in terms of the analyte amount/concentration
xD from the LOD in the signal domain SD is done by simply inverting the
calibration function (i.e. assuming a known calibration function).
@@ -68,8 +76,8 @@
# The critical value (decision limit, German Nachweisgrenze) can be obtained
# by using beta = 0.5:
lod(m, alpha = 0.01, beta = 0.5)
- # or approximated by
- 2 * lod(m, alpha = 0.01, beta = 0.5)$x
- # for the case of known, constant variance (homoscedastic data)
+}
+\seealso{
+ Examples for \code{\link{din32645}}
}
\keyword{manip}

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