Function for item distractor analysis

Description

This function performs distractor analysis for each item.

Usage

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distractor.analysis(items, key, scores, p.table = FALSE, write.csv)

Arguments

items

The unscored item response from a multiple-choice test

key

The answer key for the items

scores

An optional set of person scores associated with the item data. If scores are not provided (default) the scores are calculated using the item data and key.

p.table

If p.table=FALSE (the default) the function returns the counts of examinees who provide each answer. If p.table=TRUE the function returns the proportion of examinees who provide each answer.

write.csv

If the optional file name is provided the function will save a .csv file with the results.

Details

The scores are used to split respondents into terciles. The number (or proportion if p.table=TRUE) of examinees in each tercile giving each response is reported. The correct answer is indicated with an "*".

Value

If p.table=F counts of respondents in each tercile who chose each answer is returned as a list of tables. Each item is a separate element in the list. If p.table=T the tables contain the proportion of respondents who chose each corresponding answer.

Author(s)

John T. Willse, Zhan Shu

References

Allen, M. J. & Yen, W. M. (1979). Introduction to Measurement Theory. Lon Grove, Illinois: Waveland Press, INC.

Examples

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# Example data provided with package
data(CTTdata)
data(CTTkey)

distractor.analysis(CTTdata,CTTkey)

# Results provided in a .csv file.
distractor.analysis(CTTdata,CTTkey,p.table=TRUE,write.csv="Hello.csv")