treegram: Treegram

In SSRA: Sakai Sequential Relation Analysis

Description

This function draws a treegram for the Takeya Semantic Structure Analysis (TSSA) and Sakai Sequential Relation Analysis (SSRA)

Usage

treegram(object, select = NULL, pos = NULL, col = NULL,
  mai = c(0.2, 0, 0.2, 0.2), print.pos = TRUE, cex.text = 0.95,
  x.factor = 1.7, x.digits = 0, y.digits = 2, y.intersp = 1.45,
  cex.legend = 0.9)

Arguments

object	requires the result object of seqtab function
select	select items to be plotted
pos	position of items on the x-axis
col	color code or name for paths
mai	numeric vector of the form c(bottom, left, top, right) which gives the margin size specified in inches
print.pos	display x/y-position as legend
cex.text	text expansion factor relative to current par("cex")
x.factor	shift factor of legend position
x.digits	decimal places of x-position
y.digits	decimal places of y-position
y.intersp	legend character interspacing factor for vertical (y) line distances
cex.legend	legend character expansion factor relative to current par("cex)

Details

An item with lower item mean is located above, and an item with higher item mean is placed below in a treegram. An arrow is drawn between two items in sequential relation, namely, from the item with higher item mean to the item with lower item mean. And two items in equal relation are linked by a dashed line.

Author(s)

Takuya Yanagida [e-mail], Keiko Sakai [e-mail]

References

Takeya, M. (1991). A new test theory: Structural analyses for educational information. Tokyo: Waseda University Press.

See Also

seqtable

Examples

# Example data based on Takeya (1991)

# Sakai Sequential Relation Analysis
# ordering assesed according to the correlation coefficient and mean difference
exdat.ssra <- SSRA(exdat, output = FALSE)
exdat.seqtab <- seqtable(exdat.ssra, output = FALSE)
treegram(exdat.seqtab)

# Select items to be plotted
exdat.ssra <- SSRA(exdat, output = FALSE)
exdat.seqtab <- seqtable(exdat.ssra, output = FALSE)
treegram(exdat.seqtab, select = c("Item2", "Item3", "Item4"))

# Define position for each item on the x-axis
exdat.ssra <- SSRA(exdat, output = FALSE)
exdat.seqtab <- seqtable(exdat.ssra, output = FALSE)
treegram(exdat.seqtab, pos = c(Item5 = 1, Item4 = 3,
                               Item3 = 5, Item2 = 2, Item1 = 4))

# Change colors for each path of an item
exdat.ssra <- SSRA(exdat, output = FALSE)
exdat.seqtab <- seqtable(exdat.ssra, output = FALSE)
treegram(exdat.seqtab,
         col = c(Item5 = "red3", Item4 = "blue3",
                 Item3 = "gray99", Item2 = "darkgreen", Item1 = "darkorange2"))

SSRA documentation built on May 2, 2019, 2:14 p.m.