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NAEP Analysis and Scaling → Initial Activities → Classical Item Analysis → Overall Descriptive Statistics for Items as Defined After Scaling, Grade 8 Mathematics Combined National and State Main Assessment: 2007

Overall descriptive statistics for items as defined after scaling, grade 8 mathematics combined national and state main assessment: 2007
Statistic Item type Block M3 Block M4 Block M5 Block M6 Block M7 Block M8 Block M9 Block M10 Block M11 Block M12
† 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), 2007 Mathematics Assessment.
Number of scaled items Total 15 14 18 16 16 18 18 16 19 17
Multiple choice 11 11 9 13 12 12 10 13 16 14
Dichotomously scored constructed response 2 0 3 1 2 2 2 2 3 1
Polytomously scored constructed response 2 3 6 2 2 4 6 1 0 2
Unweighted sample size 30,400 30,400 30,500 30,500 30,700 30,800 30,500 30,600 30,600 30,500
Weighted average item score 0.46 0.44 0.61 0.51 0.51 0.54 0.48 0.52 0.55 0.49
Weighted average polyserial 0.63 0.64 0.62 0.64 0.58 0.60 0.59 0.61 0.58 0.59
Weighted alpha reliability 0.77 0.77 0.80 0.80 0.75 0.79 0.79 0.77 0.76 0.77
Weighted proportion of students attempting last item1 0.92 0.95 0.88 0.94 0.77 0.87 0.79 0.98 0.95 0.97

Last updated 02 March 2010 (JL)

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