Statistic | Type of school1 | Block R14 | Block R15 | Block R16 | Block R17 | Embedded blocks |
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† Not applicable. # Rounds to zero. 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. The Embedded Blocks column contains information about all the Reading Vocabulary items embedded within the 25-minute Reading comprehension blocks. The unweighted sample associated with the embedded items is the average unweighted sample across all embedded Reading Vocabulary items. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2009 Reading Vocabulary Assessment. |
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Number of scaled items | † | 5 | 5 | 5 | 5 | 20 |
Unweighted sample size | Public | 2,400 | 2,400 | 2,400 | 2,400 | 16,100 |
Nonpublic | # | # | # | # | 300 | |
Weighted average item score | Public | 0.55 | 0.55 | 0.70 | 0.52 | 0.60 |
Nonpublic | 0.67 | 0.68 | 0.82 | 0.61 | 0.67 | |
Weighted average polyserial | Public | 0.81 | 0.76 | 0.90 | 0.76 | 0.59 |
Nonpublic | 0.94 | 0.80 | 0.98 | 0.81 | 0.61 | |
Weighted alpha reliability | Public | 0.64 | 0.56 | 0.72 | 0.57 | † |
Nonpublic | 0.77 | 0.44 | 0.64 | 0.62 | † | |
Weighted proportion of students attempting last item2 | Public | 0.99 | 0.99 | 0.99 | 0.98 | † |
Nonpublic | 0.97 | 1.00 | 1.00 | 0.96 | † |