Item Fit Graphs
This function creates a graphical summary of the item fit information.
## Default S3 method:
fitgraph(fitEst, fitLB, fitUB, itemLabels, mainTitle = "Fit Plot",
pch = 18, fitColours = c("gray70", "gray60", "gray50", "gray40", "gray0"),
xlab = "Items", cex = 1.25, ...)
## S3 method for class 'numeric'
fitgraph(fitEst, fitLB, fitUB, itemLabels, mainTitle = "Fit Plot",
pch = 18, fitColours = c("gray70", "gray60", "gray50", "gray40", "gray0"),
xlab = "Items", cex = 1.25, ...)
## S3 method for class 'CQmodel'
fitgraph(fitEst, table = NULL, fit.type = "W", itemLabels = NULL, ...)
## S3 method for class 'character'
fitgraph(fitEst, ...)fitgraph arguments:
fitEst |
vector of item fit estimates. Could also be a CQmodel object or name of a ConQuest show file. |
fitLB |
vector of lower bounds for critical intervals for each item. |
fitUB |
vector of upper bounds for critical intervals for each item. |
itemLabels |
vector of item labels. |
mainTitle |
string containing the title of the plot. |
pch |
number or vector indicating the type of symbols to be used for each item. |
fitColours |
Color that will be used to shade the critical inteval area. |
xlab |
Label of the x-axis. The default is 'items'. |
cex |
Size of the x-axis label. |
... |
Additional parameters. |
Argument to use when passing a CQmodel object:
table |
Name of the RMP table that for which the fit will be plotted. By default |
fit.type |
Type of fit estimate that will be used, it can be |
David Torres Irribarra and Rebecca Freund.
Wilson, M. (2005). Constructing measures: An item response modeling approach.
# Generating mock data
sampleLabels <- paste('item',1:10)
fitBounds <- (abs(rnorm(10, mean = 0, sd = .05)) * 2)
fitEst <- rnorm(10, mean = 1, sd = .1)
fitLB <- 1 - fitBounds
fitUB <- 1 + fitBounds
par("mar")
# running fitgraph
fitgraph(fitEst,fitLB,fitUB,itemLabels=sampleLabels)
#From ConQuest output:
fpath <- system.file("extdata", package="WrightMap")
fitgraph(file.path(fpath,"ex2.shw"))Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.