Don't do calplot and lod for linear models from weighted

regression any more, since this is not supported (PR#8877).



git-svn-id: http://kriemhild.uft.uni-bremen.de/svn/chemCal@13 5fad18fb-23f0-0310-ab10-e59a3bee62b4

1 files changed, 28 insertions, 9 deletions

diff --git a/man/din32645.Rd b/man/din32645.Rd
index d251b7c..94486c4 100644
--- a/man/din32645.Rd
+++ b/man/din32645.Rd
@@ -14,18 +14,33 @@ data(din32645)
 m <- lm(y ~ x, data=din32645)
 calplot(m)
 (prediction <- inverse.predict(m,3500,alpha=0.01))
-# This should give 0.074 according to DIN (cited from the Dintest test data)
-round(prediction$Confidence,3)
+# This should give 0.07434 according to Dintest test data, as 
+# collected from Procontrol 3.1 (isomehr GmbH)
+round(prediction$Confidence,5)
 
-# According to Dintest, we should get 0.07, but we get 0.0759
-lod(m, alpha = 0.01)
+# According to Dintest test data, we should get 0.0698 for the critical value
+# (decision limit, "Nachweisgrenze")
+(lod <- lod(m, alpha = 0.01, beta = 0.5))
+round(lod$x,4)
 
-# In German, there is the "Erfassungsgrenze", with k = 2, 
-# and we should get 0.14 according to Dintest
-lod(m, k = 2, alpha = 0.01)
+# In German, the smallest detectable value is the "Erfassungsgrenze", and we
+# should get 0.140 according to Dintest test data, but with chemCal, we can't
+# reproduce this, 
+lod(m, alpha = 0.01, beta = 0.01) 
+# except by using an equivalent to the approximation
+# xD = 2 * Sc / A (Currie 1999, p. 118, or Orange Book, Chapter 18.4.3.7)
+lod.approx <- 2 * lod$x
+round(lod.approx, digits=3)
+# which seems to be the pragmatic definition in DIN 32645, as judging from
+# the Dintest test data. 
 
-# According to Dintest, we should get 0.21, we get 0.212
-loq(m, alpha = 0.01)
+# This accords to the test data from Dintest again, except for the last digit
+# of the value cited for Procontrol 3.1 (0.2121)
+(loq <- loq(m, alpha = 0.01))
+round(loq$x,4)
+# A similar value is obtained using the approximation 
+# LQ = 3.04 * LC (Currie 1999, p. 120)
+3.04 * lod(m,alpha = 0.01, beta = 0.5)$x
 }
 \references{
   DIN 32645 (equivalent to ISO 11843)
@@ -33,5 +48,9 @@ loq(m, alpha = 0.01)
   Dintest. Plugin for MS Excel for evaluations of calibration data. Written
   by Georg Schmitt, University of Heidelberg. 
   \url{http://www.rzuser.uni-heidelberg.de/~df6/download/dintest.htm}
+
+  Currie, L. A. (1997) Nomenclature in evaluation of analytical methods including
+  detection and quantification capabilities (IUPAC Recommendations 1995). 
+  Analytica Chimica Acta 391, 105 - 126.
 }
 \keyword{datasets}