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NAEP Analysis and Scaling → Initial Activities → Classical Item Analysis → Overall Descriptive Statistics for Items as Defined After Scaling, Grade 12 Writing National Main Assessment: 2002
Overall descriptive statistics for items as defined after scaling, grade 12 writing national main assessment: 2002
Statistic All items
Number of scaled items 20
Multiple choice 0
Dichotomously scored constructed response 0
Polytomously scored constructed response 20
Unweighted sample size 18,500
Weighted average item score .57
Weighted average polyserial .90
Weighted alpha reliability
† In NAEP writing assessments, each block contains only one item—a writing prompt to which students respond with a polytomously scored constructed response; therefore, the weighted alpha reliability estimate is not meaningful.
SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2002 Writing Assessment.

Last updated 15 April 2008 (GF)

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