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R : Copyright 2006, The R Foundation for Statistical Computing
Version 2.3.1 (2006-06-01)
ISBN 3-900051-07-0
R is free software and comes with ABSOLUTELY NO WARRANTY.
You are welcome to redistribute it under certain conditions.
Type 'license()' or 'licence()' for distribution details.
R is a collaborative project with many contributors.
Type 'contributors()' for more information and
'citation()' on how to cite R or R packages in publications.
Type 'demo()' for some demos, 'help()' for on-line help, or
'help.start()' for an HTML browser interface to help.
Type 'q()' to quit R.
> require(chemCal)
Loading required package: chemCal
[1] TRUE
> data(massart97ex3)
> attach(massart97ex3)
> yx <- split(y, x)
> ybar <- sapply(yx, mean)
> s <- round(sapply(yx, sd), digits = 2)
> w <- round(1 / (s^2), digits = 3)
> weights <- w[factor(x)]
> m <- lm(y ~ x, w = weights)
> #calplot(m)
>
> inverse.predict(m, 15, ws = 1.67) # 5.9 +- 2.5
$Prediction
[1] 5.865367
$`Standard Error`
[1] 0.892611
$Confidence
[1] 2.478285
$`Confidence Limits`
[1] 3.387082 8.343652
> inverse.predict(m, 90, ws = 0.145) # 44.1 +- 7.9
$Prediction
[1] 44.06025
$`Standard Error`
[1] 2.829162
$Confidence
[1] 7.855012
$`Confidence Limits`
[1] 36.20523 51.91526
>
> m0 <- lm(y ~ x)
> lod(m0)
$x
[1] 5.406637
$y
[1] 13.63822
>
> loq(m0)
$x
[1] 13.97767
$y
[1] 30.62355
> loq(m, w.loq = 1.67)
$x
[1] 7.346231
$y
[1] 17.90784
>
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