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NAEP Analysis and Scaling → Initial Activities → Classical Item Analysis → Overall Descriptive Statistics for Item Blocks as Defined After Scaling, Grade 12 Mathematics National Main Assessment: 2005
Overall descriptive statistics for item blocks as defined after scaling, grade 12 mathematics national main assessment: 2005
Statistic Item type Block M3 Block M4 Block M5 Block M6 Block M7 Block M8 Block M9 Block M10 Block M11 Block M12
Number of scaled items Total 17 17 18 17 18 21 18 18 18 18
Multiple choice 12 11 11 14 13 10 7 11 15 15
Dichotomously scored constructed response 1 2 4 1 0 4 5 5 2 1
Polytomously scored constructed response 4 4 3 2 5 7 6 2 1 2
Unweighted sample size 1,800 1,800 1,900 1,900 1,900 1,900 1,900 1,900 1,800 1,800
Weighted average item score 0.46 0.47 0.46 0.42 0.47 0.48 0.40 0.45 0.45 0.46
Weighted average polyserial 0.64 0.61 0.60 0.63 0.61 0.62 0.67 0.62 0.61 0.60
Weighted alpha reliability 0.81 0.77 0.78 0.78 0.80 0.79 0.82 0.77 0.79 0.78
Weighted proportion of students attempting last item1 0.86 0.92 0.89 0.90 0.87 0.68 0.69 0.91 0.98 0.95
† Not applicable.
1 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), 2005 Mathematics Assessment.

Last updated 17 February 2010 (GF)

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National Center for Education Statistics - http://nces.ed.gov
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