| DNase | R Documentation |
The DNase data frame has 176 rows and 3 columns of data
obtained during development of an ELISA assay for the recombinant
protein DNase in rat serum.
DNase
An object of class
c("nfnGroupedData", "nfGroupedData", "groupedData", "data.frame")
containing the following columns:
an ordered factor with levels 10 < ... < 3
indicating the assay run.
a numeric vector giving the known concentration of the protein.
a numeric vector giving the measured optical density (dimensionless) in the assay. Duplicate optical density measurements were obtained.
This dataset was originally part of package nlme, and that has
methods (including for [, as.data.frame, plot and
print) for its grouped-data classes.
Davidian, M. and Giltinan, D. M. (1995) Nonlinear Models for Repeated Measurement Data, Chapman & Hall (section 5.2.4, p. 134)
Pinheiro, J. C. and Bates, D. M. (2000) Mixed-effects Models in S and S-PLUS, Springer.
require(stats); require(graphics)
coplot(density ~ conc | Run, data = DNase,
show.given = FALSE, type = "b")
coplot(density ~ log(conc) | Run, data = DNase,
show.given = FALSE, type = "b")
## fit a representative run
fm1 <- nls(density ~ SSlogis( log(conc), Asym, xmid, scal ),
data = DNase, subset = Run == 1)
## compare with a four-parameter logistic
fm2 <- nls(density ~ SSfpl( log(conc), A, B, xmid, scal ),
data = DNase, subset = Run == 1)
summary(fm2)
anova(fm1, fm2)
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