From a94bd86465fe191102a2bf85a3631c83cd10db0a Mon Sep 17 00:00:00 2001 From: ranke Date: Tue, 15 Feb 2005 10:14:01 +0000 Subject: First import, for archiving purposes. git-svn-id: http://kriemhild.uft.uni-bremen.de/svn/chemCal@1 5fad18fb-23f0-0310-ab10-e59a3bee62b4 --- chm/calpredict.html | 106 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 106 insertions(+) create mode 100755 chm/calpredict.html (limited to 'chm/calpredict.html') diff --git a/chm/calpredict.html b/chm/calpredict.html new file mode 100755 index 0000000..dff8ec4 --- /dev/null +++ b/chm/calpredict.html @@ -0,0 +1,106 @@ +Estimate measurement results including confidence intervals + + + + +
calpredict(chemCal)R Documentation
+ + + + + +

Estimate measurement results including confidence intervals

+ + +

Description

+ +

+This function generates estimates for x values from y values, including +a confidence interval for the x values. The formulas in this function used +for prediction of concentrations from (replicate) measurements are taken from +the "Handbook of Chemometrics and Qualimetrics Part A" by D. L. Massart, +Vandeginste, B. G. M., Buydens, L. M. C., De Jong, S., Lewi, P. J. and +Smeyers-Verbeke, J, Elsevier, Amsterdam, 1997 and from the EURACHEM/CITAC +report on "Quantifying uncertainty in analytical measurement", 2000, +pp. 111f. +

+ + +

Usage

+ +
+  calpredict(yobs,xi,yi,xunit="",level=0.95,intercept=FALSE,syobs=FALSE)
+
+ + +

Arguments

+ + + + + + + + + + + + + + + + +
yobs +A numeric vector containing the observed data. +
xi +A vector of x values of the calibration. +
yi +A vector of y values of the calibration. +
xunit +The unit of the given values on the x axis as a character string. +
level +The desired confidence level for the confidence interval of the +estimates. Defaults to 0.95. +
intercept +Logical value determining if an intercept is to be fitted or not. +Default is FALSE. +
syobs +If TRUE, a standard deviation for the given y values is +calculated, and the resulting confidence interval will +include this variability (not validated yet). If FALSE (default), this +standard deviation is not included in the +confidence interval. If a numeric value is given, +it is used for the standard deviation of "real samples", +in addition to the standard deviation of the y values +in the calibration (also not validated yet). +
+ +

Value

+ +

+A list containing the estimate, its standard deviation and its +confidence interval.

+ +

Author(s)

+ +

+Johannes Ranke +jranke@uni-bremen.de +http://www.uft.uni-bremen.de/chemie/ranke +

+ + +

Examples

+ +
+data(pahCalibration)
+attach(pahCalibration)
+y <- c(51.2,51.4,51.1,51.8)
+estimate <- calpredict(y,conc,acenaphthene,xunit="mg/L")
+
+ + + +
[Package Contents]
+ + -- cgit v1.2.1