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Last data update: 2014.03.03

R: Add threshold lines to a plot (three-state setting)

lines.thres3

R Documentation

Add threshold lines to a plot (three-state setting)

Description

The function includes vertical lines for the thresholds and confidence intervals in a plot created with plot.thres3().

Usage

## S3 method for class 'thres3'
lines(x, ci = TRUE, which.boot = c("norm", "perc"),
  col = 1, lty = c(1, 2), lwd = 1, ...)

Arguments

`x`	an object of class `thres3`.
`ci`	should the confidence intervals be plotted? Default, `TRUE`.
`which.boot`	in case `x` contains confidence intervals computed by bootstrapping, which one should be printed? the user can choose between `"norm"` (based on normal distribution) or `"perc"` (based on percentiles). Default, `"norm"`. This argument is ignored if parametric confidence intervals were computed.
`col`	color for the thresholds and their corresponding confidence intervals. Default, 1.
`lty`	a 2-dimensional vector containing: `lty[1]`: line type for the thresholds `lty[2]`: line type for the confidence intervals Default, `c(1, 2)`.
`lwd`	line width for the thresholds and their corresponding confidence intervals. Default, 1.
`...`	further arguments to be passed to `abline()`.

Value

With a plot.thres3 open, this function adds lines for the required threshold estimates.

References

Skaltsa K, Jover L, Fuster D, Carrasco JL. (2012). Optimum threshold estimation based on cost function in a multistate diagnostic setting. Statistics in Medicine, 31:1098-1109.

Examples

set.seed(1234)
n <- 100
k1 <- rlnorm(n)
k2 <- rnorm(n, 3, 1)
k3 <- rnorm(n, 5, 1)
rho <- c(1/3, 1/3, 1/3)

# assuming trinormality
start <- c(mean(k1), mean(k3))
thres1 <- thres3(k1, k2, k3, rho, dist1="norm", dist2="norm",
                 dist3="norm", start=start, ci.method="param") 

# not assuming trinormality
start2 <- c(0.05, 0.6, 0.5, 0.95)
set.seed(2014)
thres2 <- thres3(k1, k2, k3, rho, start=start2, B=1000,
                ci.method="boot", dist1="lnorm", dist2="norm",
                dist3="norm") 
plot(thres2, leg.pos="topright", leg.cex=0.8, col=1:4)
lines(thres1, col=5)