diff options
Diffstat (limited to 'man')
| -rw-r--r-- | man/inverse.predict.Rd | 18 | ||||
| -rw-r--r-- | man/lod.Rd | 12 | ||||
| -rw-r--r-- | man/loq.Rd | 12 | ||||
| -rw-r--r-- | man/massart97ex3.Rd | 55 |
4 files changed, 48 insertions, 49 deletions
diff --git a/man/inverse.predict.Rd b/man/inverse.predict.Rd index 925f3e9..6bea72c 100644 --- a/man/inverse.predict.Rd +++ b/man/inverse.predict.Rd @@ -59,15 +59,15 @@ p. 200 } \examples{ - 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) +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) - inverse.predict(m, 15, ws = 1.67) # 5.9 +- 2.5 +inverse.predict(m, 15, ws = 1.67) # 5.9 +- 2.5 } \keyword{manip} @@ -69,13 +69,13 @@ Analytica Chimica Acta 391, 105 - 126. } \examples{ - data(din32645) - m <- lm(y ~ x, data = din32645) - lod(m) +data(din32645) +m <- lm(y ~ x, data = din32645) +lod(m) - # The critical value (decision limit, German Nachweisgrenze) can be obtained - # by using beta = 0.5: - lod(m, alpha = 0.01, beta = 0.5) +# The critical value (decision limit, German Nachweisgrenze) can be obtained +# by using beta = 0.5: +lod(m, alpha = 0.01, beta = 0.5) } \seealso{ Examples for \code{\link{din32645}} @@ -63,13 +63,13 @@ and therefore not tested. Feedback is welcome. } \examples{ - data(massart97ex3) - attach(massart97ex3) - m <- lm(y ~ x) - loq(m) +data(massart97ex3) +attach(massart97ex3) +m <- lm(y ~ x) +loq(m) - # We can get better by using replicate measurements - loq(m, n = 3) +# We can get better by using replicate measurements +loq(m, n = 3) } \seealso{ Examples for \code{\link{din32645}} diff --git a/man/massart97ex3.Rd b/man/massart97ex3.Rd index e7cd383..efdcf02 100644 --- a/man/massart97ex3.Rd +++ b/man/massart97ex3.Rd @@ -11,38 +11,37 @@ observations of y for each level. } \examples{ - 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) +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) - # The following concords with the book p. 200 - inverse.predict(m, 15, ws = 1.67) # 5.9 +- 2.5 - inverse.predict(m, 90, ws = 0.145) # 44.1 +- 7.9 +# The following concords with the book p. 200 +inverse.predict(m, 15, ws = 1.67) # 5.9 +- 2.5 +inverse.predict(m, 90, ws = 0.145) # 44.1 +- 7.9 - # The LOD is only calculated for models from unweighted regression - # with this version of chemCal - m0 <- lm(y ~ x) - lod(m0) +# The LOD is only calculated for models from unweighted regression +# with this version of chemCal +m0 <- lm(y ~ x) +lod(m0) - # Limit of quantification from unweighted regression - m0 <- lm(y ~ x) - loq(m0) +# Limit of quantification from unweighted regression +loq(m0) - # For calculating the limit of quantification from a model from weighted - # regression, we need to supply weights, internally used for inverse.predict - # If we are not using a variance function, we can use the weight from - # the above example as a first approximation (x = 15 is close to our - # loq approx 14 from above). - loq(m, w.loq = 1.67) - # The weight for the loq should therefore be derived at x = 7.3 instead - # of 15, but the graphical procedure of Massart (p. 201) to derive the - # variances on which the weights are based is quite inaccurate anyway. +# For calculating the limit of quantification from a model from weighted +# regression, we need to supply weights, internally used for inverse.predict +# If we are not using a variance function, we can use the weight from +# the above example as a first approximation (x = 15 is close to our +# loq approx 14 from above). +loq(m, w.loq = 1.67) +# The weight for the loq should therefore be derived at x = 7.3 instead +# of 15, but the graphical procedure of Massart (p. 201) to derive the +# variances on which the weights are based is quite inaccurate anyway. } \source{ Massart, L.M, Vandenginste, B.G.M., Buydens, L.M.C., De Jong, S., Lewi, P.J., |