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NAEP Analysis and Scaling → Initial Activities → Classical Item Analysis → Item-Level Descriptive Statistics by Public- and Nonpublic-School Sessions, as Defined After Scaling, Grade 12 Writing National Main Assessment: 2002
Item-level descriptive statistics by public- and nonpublic-school sessions, as defined after scaling, grade 12 writing national main assessment: 2002
Statistic Type of school1 All items2
Number of scaled items 20
Unweighted sample size Public 14,300
Nonpublic 4,200
Weighted average item score Public 0.56
Nonpublic 0.65
Weighted average polyserial Public 0.90
Nonpublic 0.90
1 Nonpublic-school sample includes only Catholic and private schools.
2  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 and does not appear in this table.
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 16 April 2008 (GF)

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