Rwinsteps (version 1.0-1.1)

ifile: Item and Person Summary Files

Description

An “ifile” is a data frame containing statistical output for a set of items. A “pfile” is a data frame containing statistical output for a group of people, or examinees. These functions create, read, and convert to “ifile” and “pfile” objects.

Usage

ifile(measure, entry = 1:length(measure), ...)
pfile(measure, entry = 1:length(measure), ...)
as.ifile(x)
as.pfile(x)
read.ifile(filename, skip = 1, col.names, sep = ",", ...)
read.pfile(filename, skip = 1, col.names, sep = ",", ...)

Arguments

measure

numeric vector of item locations

entry

item position numbers, normally a sequence from 1 to the number of items

x

a data frame with items as rows, containing, at a minimum, columns titled “measure” and “entry”

filename

path to the file, which is assumed to be a table in 'csv' format

skip

number of header lines to skip, defaulting to 1

col.names

vector of column names to be added to the file after it is read in

sep

the field separator character, sent to read.table, defaulting to comma separated values

…

For ifile and pfile, additional variables, as vectors of the same length as measure, to be included in the ifile or pfile; for read.ifile and read.pfile, further arguments passed to read.table

Value

A data frame of class “ifile” or “pfile”

Details

The ifile contains item-level information, and the pfile person-level information, based on a fit of the Rasch model to a set of item-response data.

Using read.ifile and read.pfile, the ifile and pfile are read in as 'csv' files, i.e., tables with sep = ",". These functions are simple wrappers for the function read.csv.

See Also

read.ifile, plot.ifile

Examples

# NOT RUN {
imeasure <- rnorm(5)
ifile(imeasure, name = paste("item", 1:5, sep = ""))
as.ifile(data.frame(measure = imeasure, entry = 1:5))

pmeasure <- rnorm(3)
pfile(pmeasure, name = c("Skeeter", "Shira", "Soto"))
as.pfile(data.frame(measure = pmeasure, entry = 1:3))
# }