Statistic | Item type | Block M3 | Block M4 | Block M5 | Block M6 | Block M7 | Block M8 | Block M9 | Block M10 | Block M11 | Block M12 |
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† 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), 2009 Mathematics Assessment. |
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Number of scaled items | Total | 15 | 15 | 15 | 16 | 15 | 19 | 16 | 16 | 16 | 16 |
Multiple choice | 10 | 11 | 7 | 13 | 9 | 13 | 11 | 12 | 10 | 12 | |
Dichtomously scored constructed response | 1 | 1 | 3 | 1 | 2 | 2 | 0 | 2 | 0 | 1 | |
Polytomously scored constructed response | 4 | 3 | 5 | 2 | 4 | 4 | 5 | 2 | 6 | 3 | |
Unweighted sample size | † | 33,400 | 33,500 | 33,600 | 34,100 | 33,300 | 34,000 | 33,400 | 34,300 | 33,600 | 34,300 |
Weighted average item score | † | 0.50 | 0.52 | 0.52 | 0.60 | 0.50 | 0.56 | 0.54 | 0.57 | 0.55 | 0.52 |
Weighted average polyserial | † | 0.62 | 0.59 | 0.57 | 0.60 | 0.58 | 0.53 | 0.63 | 0.60 | 0.55 | 0.57 |
Weighted alpha reliability | † | 0.77 | 0.73 | 0.78 | 0.76 | 0.75 | 0.76 | 0.77 | 0.74 | 0.71 | 0.72 |
Weighted proportion of students attempting last item1 | † | 0.96 | 0.90 | 0.70 | 0.94 | 0.89 | 0.69 | 0.96 | 0.96 | 0.94 | 0.91 |