Usage
star.nominalcat(formula, data, xij, conf.int = FALSE, symmetric = TRUE,
pred.coding = "reference", printpvalues = TRUE, test.rel = TRUE, refLevel = 1,
maxit = 100, scale = TRUE, nlines = NULL, select = NULL, catstar = TRUE,
dist.x = 1, dist.y = 1, dist.cov = 1, dist.cat = 1, xpd = TRUE, main = "",
lwd.stars = 1.2, col.fill = "gray90", col.circle = "black", lwd.circle = 1,
lty.circle = "longdash", lty.conf = "dotted", cex.labels = 1, cex.cat = 0.8,
xlim = NULL, ylim = NULL)Arguments
formula
An object of class formula. Formula for the multinomial logit model to be fitted and visualized.
data
An object of class data.frame containing the covariates used in formula.
xij
An object of class list, used if category-specific covariates are to be inlcuded. Every element is a formula referring to one of the category-specific covariates. For details see help for xij in conf.int
If TRUE, confidence intervals are drawn.
symmetric
Which side constraint for the coefficients in the multinomial logit model shall be used for the plot?
Default TRUE uses symmetric side constraints, FALSE uses the reference category specified by refLevel.
pred.coding
Which coding for categorical predictors with more than two categories is to be used?
Default pred.coding="reference" uses the first category as reference category, the alternative pred.coding="effect" uses effect coding equival
printpvalues
If TRUE, p-values for the respective coefficients are printed besides the category labels.
P-values are recieved by a Wald test.
test.rel
Provides a Likelihood-Ratio-Test to test the relevance of the explanatory covariates.
The corresponding p-values will be printed behind the covariates labels. test.rel=FALSE might
save a lot of time.
refLevel
Reference category for multinomial logit model. Ignored if symmetric=TRUE. See also
multinomial. maxit
Maximal number of iterations to fit the multinomial logit model. See also
vglm.control. scale
If TRUE, the stars are scaled to equal maximal ray length.
nlines
If specified, nlines gives the number of lines in which the effect stars are plotted.
select
Numeric vector to choose only a subset of the stars to be plotted. Default is to plot all stars. Numbers refer to total amount of predictors, including intercept and dummy variables.
catstar
A logical argument to specify if all category-specific effects in the model should be visualized with an additional star. Ignored if xij=NULL.
dist.x
Optional factor to increase/decrease distances between the centers of the stars on the x-axis. Values greater than
1 increase, values smaller than 1 decrease the distances.
dist.y
Optional factor to increase/decrease distances between the centers of the stars on the y-axis. Values greater than
1 increase, values smaller than 1 decrease the distances.
dist.cov
Optional factor to increase/decrease distances between the stars and the covariates labels above the stars. Values greater than
1 increase, values smaller than 1 decrease the distances.
dist.cat
Optional factor to increase/decrease distances between the stars and the category labels around the stars. Values greater than
1 increase, values smaller than 1 decrease the distances.
xpd
If FALSE, all plotting is clipped to the plot region, if TRUE, all plotting is clipped to the figure region,
and if NA, all plotting is clipped to the device region. See also
main
An overall title for the plot. See also plot. lwd.stars
Line width of the stars. See also lwd in par. col.fill
Color of background of the circle. See also col in par. col.circle
Color of margin of the circle. See also col in par. lwd.circle
Line width of the circle. See also lwd in par. lty.circle
Line type of the circle. See also lty in par. lty.conf
Line type of confidence intervals. Ignored, if conf.int=FALSE. See also lty
in par. cex.labels
Size of labels for covariates placed above the corresponding star. See also cex
in par. cex.cat
Size of labels for categories placed around the corresponding star. See also cex
in par. xlim
Optional specification of the x coordinates ranges. See also xlim in plot.window ylim
Optional specification of the y coordinates ranges. See also ylim in plot.window