Lines method for ic_sp2 objects

Usage

# S3 method for class 'ic_sp2'
lines(x, y, type = "s", strata, ...)

Arguments

x: an object of class 'ic_sp2'
y: ignored
type: the type of plot to produce, default is "l" for lines
strata: Optional vector of indices to subset the strata to be plotted.
...: additional arguments passed to the lines function

Details

Due to the interval censoring, the survival curves are not unique, so two lines are drawn for each curve: one for the lower bound and one for the upper bound of the interval. A pair of lines is drawn for each stratum, if strata are present in the model. Therefore to unambiguously specify graphics parameters such as colour or line type, the user should specify them as a vector of length equal to the number of strata (for strata specific pars) or twice the number of strata (for line specific pars, e.g. strata 1 lower, strata 1 upper, strata 2 lower, strata 2 upper).