Calculate Wald-Profiles

Description

Transforms a signed root deviance profile of a mcprofile object into a profile of Wald-type statistics

Usage

wald(object)

Arguments

Value

An object of class mcprofile with a wald profile in the srdp slot.

Author(s)

Daniel Gerhard

See Also

mcprofile

Examples

#######################################
## cell transformation assay example ##
#######################################

str(cta)
## change class of cta$conc into factor
cta$concf <- factor(cta$conc, levels=unique(cta$conc))

ggplot(cta, aes(y=foci, x=concf)) + 
   geom_boxplot() +
   geom_dotplot(binaxis = "y", stackdir = "center", binwidth = 0.2) +    
   xlab("concentration")
   

# glm fit assuming a Poisson distribution for foci counts
# parameter estimation on the log link
# removing the intercept
fm <- glm(foci ~ concf-1, data=cta, family=poisson(link="log"))

### Comparing each dose to the control by Dunnett-type comparisons
# Constructing contrast matrix
library(multcomp)
CM <- contrMat(table(cta$concf), type="Dunnett")

# calculating signed root deviance profiles
(dmcp <- mcprofile(fm, CM))
# computing profiles for the modified likelihood root
wp <- wald(dmcp)

plot(wp)

# comparing confidence intervals
confint(wp)
confint(dmcp)

Results