This example uses the MathScienceTest.jmp sample data table, which is a subset of the data from the Third International Mathematics and Science Study (TIMSS) conducted in 1996. The data table contains scores (1 = correct or 0 = incorrect) for 1263 subjects on 14 questions. You examine the first four questions to understand the relationship between questions and respondent’s mathematical ability. The questions on the test are the items that are used to measure the latent mathematical ability. Fit a 2PL model to this data.
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Select Analyze > Consumer Research > Item Analysis.

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Note: Individuals with all incorrect or all correct answers are not included in the analysis. For more information, see Fitting the IRT Model.
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Click the Item Analysis red triangle menu, and select Number of Plots Across.

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