| compParm {drc} | R Documentation |
Compare parameters from different assays, either by means of ratios or differences.
compParm(object, strVal, operator = "/", od = FALSE)
object |
an object of class 'drc'. |
strVal |
a name of parameter to compare. |
operator |
a character. If equal to "/" (default) parameter ratios are compared. If equal to "-" parameter differences are compared. |
od |
logical. If TRUE adjustment for over-dispersion is used. |
The function compares actual parameter estimates, and therefore the results depend on the parameterisation used. Probably it is most useful
in combination with 'collapse' arguments (in drm) that are data frames or lists with formulas without intercept (-1).
A matrix with columns containing the estimates, estimated standard errors, values of t-statistics and p-values for the null hypothesis that
the ratio equals 1 or that the difference equals 0 (depending on the operator argument).
No adjustment for multiplicity is applied. See p.adjust on how to do adjust p-values.
Christian Ritz
# Fitting a model with names assigned to the parameters!
spinach.m1 <- drm(SLOPE~DOSE, CURVE, data = spinach,
fct = LL.4(names = c("b", "lower", "upper", "ed50")))
## Calculating ratios of parameter estimates for the parameter named "ed50"
compParm(spinach.m1, "ed50")
## Calculating differences between parameter estimates for the parameter named "ed50"
compParm(spinach.m1, "ed50", "-")