itemanalysis2: Classical Test Theory Item Analysis for Polytomous Items

Description Usage Arguments Details Value Author(s) See Also Examples

Description

Classical Test Theory Item Analysis for Polytomous Items

Usage

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itemanalysis2(data, options, ngroup = ncol(data) + 1, correction = TRUE)

Arguments

data

a data frame with N rows and m columns, with N denoting the number of subjects and m denoting the number of items.

options

a vector of numerical code of the response categories available for the items such as c(0,1,2,3). The minumum score is assumed to be 0.

ngroup

number of score groups to be use for plotting the item trace lines

correction

TRUE or FALSE. If it is TRUE, then an adjustment is made for point-biserial correlation.

Details

to be added later

Value

plots

a list object storing the item trace line plots for each item

Author(s)

Cengiz Zopluoglu

See Also

itemanalysis1 for classical item analysis of multiple-choice test items

Examples

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    data(timss2011_usa)

    timss2011_usa$Q14B <- recode(var = timss2011_usa$Q14B,
                                 recodes = "c(0)=3;c(1)=2;c(2)=1;c(3)=0")

    timss2011_usa$Q14C <- recode(var = timss2011_usa$Q14C,
                                 recodes = "c(0)=3;c(1)=2;c(2)=1;c(3)=0")

    item.analysis <- itemanalysis2(data=timss2011_usa,
                                   options=c(0,1,2,3),
                                   ngroup=18,
                                   correction=FALSE)

    # item.analysis$plots[[1]]   # Item Trace Line for the first item
    # item.analysis$plots[[2]]   # Item Trace Line for the second item
    # item.analysis$plots[[3]]   # Item Trace Line for the third item
    # item.analysis$plots[[4]]   # Item Trace Line for the fourth item
    # item.analysis$plots[[5]]   # Item Trace Line for the fifth item
    # item.analysis$plots[[6]]   # Item Trace Line for the sixth item

itemanalysis documentation built on May 2, 2019, 1:05 p.m.