calplot. chemCal 0.1-35.900

Usage

calplot(object, xlim = c("auto", "auto"), ylim = c("auto", "auto"), xlab = "Concentration", ylab = "Response", alpha=0.05, varfunc = NULL)

+ +

Arguments

object: + A univariate model object of class lm or + rlm + with model formula y ~ x or y ~ x - 1. +
xlim: + The limits of the plot on the x axis. +
ylim: + The limits of the plot on the y axis. +
xlab: + The label of the x axis. +
ylab: + The label of the y axis. +
alpha: + The error tolerance level for the confidence and prediction bands. Note that this + includes both tails of the Gaussian distribution, unlike the alpha and beta parameters + used in lod (see note below). +
varfunc: + The variance function for generating the weights in the model. + Currently, this argument is ignored (see note below). +

+ +

Description

+ +

Produce graphics of calibration data, the fitted model as well + as confidence, and, for unweighted regression, prediction bands.

+ +

Value

+ +

+ A plot of the calibration data, of your fitted model as well as lines showing + the confidence limits. Prediction limits are only shown for models from + unweighted regression. +

+ +

Note

+ +

Prediction bands for models from weighted linear regression require weights + for the data, for which responses should be predicted. Prediction intervals + using weights e.g. from a variance function are currently not supported by + the internally used function predict.lm, therefore, + calplot does not draw prediction bands for such models.

+ +

It is possible to compare the calplot prediction bands with the + lod values if the lod() alpha and beta parameters are + half the value of the calplot() alpha parameter.

+ +

Examples

data(massart97ex3)
+m <- lm(y ~ x, data = massart97ex3)
+calplot(m)
+
+

+ + + +

Author

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