Blog Archives

WrightMap 1.1 Ancillary Antelope Released

April 12, 2014
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WrightMap 1.1 Ancillary Antelope Released

The new version of WrightMap (Ancillary Antelope) is now available on CRAN. Remember that you can visit the package tutorials on our website. This new version includes: - New function to create fit graphs like the example below. - Parameter conversion: Function for calculating Thurstonian thresholds from Master’s deltas. - New examples. - Added axis range controls. - Made histogram...

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Wright Map Tutorial – Part 3

March 25, 2014
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Wright Map Tutorial – Part 3

In this part of the tutorial, we’ll show how to load ConQuest output to make a CQmodel object and then WrightMaps. We’ll also show how to turn deltas into thresholds. All the example files here are available in the /inst/extdata folder of the github. If you download the latest version of the package, they should be in a folder...

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WrightMap Tutorial – Part 2

March 24, 2014
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WrightMap Tutorial – Part 2

Plotting Multidimensional & Polytomous Models Remember: you can find the other parts of the tutorial here: Part 1: Plotting Unidimensional Dichotomous Models Part 3: Using Conquest Output & Making Thresholds Multidimensional models In Part 1, we reviewed how to install the package from GitHub and how to customize unidimensional and dichotomous models. Now in Part 2, we’ll look at graphing some...

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Recoding Polytomous Items with Missing Categories

December 26, 2012
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This function helps prepare data for analysis with models that require polytomous items to be coded from 0 to N without missing categories, such as the Partial Credit Model (Masters, 1982). When there are no missing categories, an item that was suppos...

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Simple data simulator for the 2PL model

December 21, 2012
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The function: This is a very simple data simulator for a 2PL Model. This is just to get you started, from here is easy to add function parameters for indicating item locations and slopes or person distribution characteristics. The function accepts on...

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Simple data simulator for the Rasch Model

December 21, 2012
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The function: This is a very simple data simulator for the Rasch Model.This is just to get you started, from here is easy to add function parameters for indicating item locations or person distribution characteristics. The function accepts only two p...

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