From f4fcef8228ebd5a1a73bc6edc47b5efa259c2e20 Mon Sep 17 00:00:00 2001 From: Johannes Ranke Date: Wed, 23 Mar 2022 10:32:36 +0100 Subject: Use 'investr' conditionally in tests, updates Most prominently, a README was added, giving a nice overview for the people visiting the github page, the package page on CRAN, or the online docs at pkgdown.jrwb.de. The maintainer e-mail address was also updated. --- docs/reference/lod.html | 236 ++++++++++++++++-------------------------------- 1 file changed, 80 insertions(+), 156 deletions(-) (limited to 'docs/reference/lod.html') diff --git a/docs/reference/lod.html b/docs/reference/lod.html index 42fc533..a2d66ce 100644 --- a/docs/reference/lod.html +++ b/docs/reference/lod.html @@ -1,74 +1,19 @@ - - - - - - - -Estimate a limit of detection (LOD) — lod • chemCal - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -Estimate a limit of detection (LOD) — lod • chemCal - - - - - - - - - - - - - + + -
-
- -
- -
+

Estimate a limit of detection (LOD)

@@ -137,62 +69,52 @@ one-sided significance test).

- 
lod(object, ..., alpha = 0.05, beta = 0.05, method = "default", tol = "default")
+
+ 
lod(object, ..., alpha = 0.05, beta = 0.05, method = "default", tol = "default")
+
-

Arguments

- - - - - - - - - - - - - - - - - - - - - - - - - - -
object

A univariate model object of class lm or - rlm +

+

Arguments

+
object
+

A univariate model object of class lm or + rlm with model formula y ~ x or y ~ x - 1, - optionally from a weighted regression.

...

Placeholder for further arguments that might be needed by - future implementations.

alpha

The error tolerance for the decision limit (critical value).

beta

The error tolerance beta for the detection limit.

method

The “default” method uses a prediction interval at the LOD + optionally from a weighted regression.

+
...
+

Placeholder for further arguments that might be needed by + future implementations.

+
alpha
+

The error tolerance for the decision limit (critical value).

+
beta
+

The error tolerance beta for the detection limit.

+
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 “din” method uses the prediction interval at - x = 0 as an approximation.

tol

When the “default” method is used, the default tolerance + The “din” method uses the prediction interval at + x = 0 as an approximation.

+
tol
+

When the “default” method is used, the default tolerance for the LOD on the x scale is the value of the smallest non-zero standard - divided by 1000. Can be set to a numeric value to override this.

- -

Value

- + divided by 1000. Can be set to a numeric value to override this.

+
+
+

Value

A list containig the corresponding x and y values of the estimated limit of detection of a model used for calibration.

-

Note

- +
+
+

Note

- 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). - The calculation of a LOD from weighted calibration models requires - a weights argument for the internally used predict.lm + a weights argument for the internally used predict.lm function, which is currently not supported in R.

-

References

- +
+
+

References

Massart, L.M, Vandenginste, B.G.M., Buydens, L.M.C., De Jong, S., Lewi, P.J., Smeyers-Verbeke, J. (1997) Handbook of Chemometrics and Qualimetrics: Part A, Chapter 13.7.8

@@ -202,53 +124,55 @@

Currie, L. A. (1997) Nomenclature in evaluation of analytical methods including detection and quantification capabilities (IUPAC Recommendations 1995). Analytica Chimica Acta 391, 105 - 126.

-

See also

- -

Examples for din32645

- -

Examples

- 
m <- lm(y ~ x, data = din32645)
-lod(m) 
-
#> $x
-#> [1] 0.08655484
-#> 
-#> $y
-#> [1] 3317.154
-#> 

-# The critical value (decision limit, German Nachweisgrenze) can be obtained
-# by using beta = 0.5:
-lod(m, alpha = 0.01, beta = 0.5)
-
#> $x
-#> [1] 0.0698127
-#> 
-#> $y
-#> [1] 3155.393
-#>
+
+
+

See also

+

Examples for din32645

+
+ +
+

Examples

+ 
m <- lm(y ~ x, data = din32645)
+lod(m) 
+#> $x
+#> [1] 0.08655484
+#> 
+#> $y
+#> [1] 3317.154
+#> 
+
+# The critical value (decision limit, German Nachweisgrenze) can be obtained
+# by using beta = 0.5:
+lod(m, alpha = 0.01, beta = 0.5)
+#> $x
+#> [1] 0.0698127
+#> 
+#> $y
+#> [1] 3155.393
+#> 
+
+
+
- - - + + -- cgit v1.2.1