effect: Draw a change in the probability distribution on an existing...

In plot3logit: Ternary Plots for Trinomial Regression Models

Draw a change in the probability distribution on an existing plot

Description

Given the first two probabilities of a trinomial distribution before and after a change, effect() adds an arrow to an existing ternary plot. If the probability distribution does not change, a point (instead of an arrow) is added to the plot.

Usage

effect(x, y, ..., length = 0.05)

Arguments

x, y	numeric vectors of the first two probabilities. If the probability distribution is unchanged, x and y should have length one.
...	other graphical parameters such as xpd and the line characteristics lend, ljoin and lmitre. See graphics::par().
length	length of the edges of the arrow head (in inches).

Warning

Only when effect() is passed to Ternary::AddToTernary() as the first argument, arrows and points are drawn consistently with ternary coordinate system, otherwise effect draws both arrows and points according to a Cartesian coorinate system centered on (0,0.5,0.5).

plot3logit documentation built on Dec. 20, 2025, 1:07 a.m.