LenthPlot: Lenth's Plot of Effects

In daewr: Design and Analysis of Experiments with R

Lenth's Plot of Effects

Description

Plot of the factor effects with significance levels based on robust estimation of contrast standard errors.

Usage

LenthPlot(obj, alpha = 0.05, plt = TRUE, limits = TRUE,
    xlab = "factors", ylab = "effects", faclab = NULL, cex.fac = graphics::par("cex.lab"),
    cex.axis=graphics::par("cex.axis"), adj = 1, ...)

Arguments

obj	object of class lm or vector with the factor effects.
alpha	numeric. Significance level used for the margin of error (ME) and simultaneous margin of error (SME). See Lenth(1989).
plt	logical. If TRUE, a spikes plot with the factor effects is displayed. Otherwise, no plot is produced.
limits	logical. If TRUE ME and SME limits are displayed and labeled.
xlab	character string. Used to label the x-axis. "factors" as default.
ylab	character string. Used to label the y-axis. "effects" as default.
faclab	list with components idx (numeric vector) and lab (character vector). The idx entries of effects vector (taken from obj) are labelled as lab. The rest of the effect names are blanked. If NULL all factors are labelled using the coefficients' name.
cex.fac	numeric. Character size used for the factor labels.
cex.axis	numeric. Character size used for the axis.
adj	numeric between 0 and 1. Determines where to place the "ME" (margin of error) and the "SME" (simultaneous margin of error) labels (character size of 0.9*cex.axis). 0 for extreme left hand side, 1 for extreme right hand side.
...	extra parameters passed to plot.

Details

If obj is of class lm, 2*coef(obj) is used as factor effect with the intercept term removed. Otherwise, obj should be a vector with the factor effects. Robust estimate of the contrasts standard error is used to calculate marginal (ME) and simultaneous margin of error (SME) for the provided significance (1 - alpha) level. See Lenth(1989). Spikes are used to display the factor effects. If faclab is NULL, factors are labelled with the effects or coefficient names. Otherwise, those faclab\$idx factors are labelled as faclab\$lab. The rest of the factors are blanked.

Value

The function is called mainly for its side effect. It returns a vector with the value of alpha used, the estimated PSE, ME and SME.

Author(s)

Ernesto Barrios. Extension provided by Kjetil Kjernsmo (2013).

References

Lenth, R. V. (1989). "Quick and Easy Analysis of Unreplicated Factorials". Technometrics Vol. 31, No. 4. pp. 469–473.

daewr documentation built on Sept. 9, 2023, 9:06 a.m.