R: Item level perspective plots or contour plots for spfa models

plotitem.cont {spfa}

R Documentation

Item level perspective plots or contour plots for spfa models

Description

For continuous response data use plotitem.cont whereas discrete response data use plotitem.disc. For joint continuous and discrete data, use plotgroup.

Usage

plotitem.cont(
  param,
  nquad = 21,
  npoints = 101,
  xlim = c(-2.5, 2.5),
  ylim = c(0, 1),
  normal = TRUE,
  FUN = NULL,
  plot = TRUE,
  type = "contour",
  ...
)

plotitem.disc(
  param,
  ncat,
  npoints = 101,
  xlim = c(-2.5, 2.5),
  normal = TRUE,
  FUN = NULL,
  plot = TRUE,
  col = 1:ncat,
  lty = rep(1, ncat),
  ...
)

plotgroup(
  param,
  nquad = 21,
  npoints = 101,
  lim = c(-2.5, 2.5),
  normal = TRUE,
  plot = TRUE,
  type = "contour",
  ...
)

Arguments

`param`	parameter vector estimated from `spfa` model
`nquad`	an integer value of number of quadrature points. Default is 21
`npoints`	an integer value of number of x and y levels in the plot
`xlim`	the x limits of the plot. Two numerical values indicating the lower and upper limits
`ylim`	the y limits of the plot. Two numerical values indicating the lower and upper limits of the density. Note y is rescaled to a uniform [0,1] distribution.
`normal`	a logical value `TRUE` or `FALSE` indicating which density is used to rescale y.
`FUN`	a user supplied function to rescale.
`plot`	a logical value `TRUE` or `FALSE` indicating whether the plot is visualized.
`type`	the type of plot to be visualized. The default is the contour plot `contour`. It can also be changed to "`persp`" indicating perspective plots.
`...`	additional arguments passed to `contour` and `persp`
`ncat`	an integer value indicating the number of categories for the discrete item.
`col`	color of the line.
`lty`	line type
`lim`	limit

Value

plots. Item level perspective and contour plot

Examples


# Contour plot of the first item 

plotitem.cont(spfa::spfa_example$par[[1]])