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NAEP Analysis and Scaling → Initial Activities → Classical Item Analysis → Block-Level Descriptive Statistics by Public- and Nonpublic-School Sessions, as Defined After Scaling, Grade 8 Geography National Main Assessment (Accommodations Not Permitted [R2]): 2001
Block-level descriptive statistics by public- and nonpublic-school sessions, as defined after scaling, grade 8 geography national main assessment (accommodations not permitted [R2]): 2001
Statistic Type of school1 Block G3  Block G4  Block G5  Block G6  Block G7  Block G8  Block G9 
Number of scaled items 17 16 17 16 14 17 25
Unweighted sample size Public 1,900 1,900 1,900 1,900 1,900 1,900 2,000
Nonpublic 300 300 300 300 300 300 300
Weighted average item score Public 0.49 0.52 0.49 0.40 0.44 0.67 0.50
Nonpublic 0.57 0.59 0.55 0.46 0.51 0.74 0.56
Weighted average polyserial Public 0.57 0.50 0.61 0.49 0.58 0.61 0.53
Nonpublic 0.57 0.48 0.55 0.48 0.57 0.59 0.49
Weighted alpha reliability Public 0.76 0.68 0.78 0.69 0.73 0.76 0.80
Nonpublic 0.75 0.62 0.71 0.67 0.73 0.68 0.75
Weighted proportion of students attempting last item2 Public 0.98 0.96 0.96 0.91 0.73 0.93 0.99
Nonpublic 0.99 0.99 0.97 0.88 0.70 0.99 0.99
† Not applicable.
1 Nonpublic-school sample includes only Catholic and private schools.
2 The "Weighted proportion of students attempting last item" is equal to 1 - (Percent not responding to last item /100).
NOTE: Item statistics in this table are described on the page Blocks of Items.
SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2001 Geography Assessment.
Last updated 10 July 2008 (GF)

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