NAEP Analysis and Scaling → Initial Activities → Classical Item Analysis → Block-Level Descriptive Statistics as Defined After Scaling, Grade 8 Writing National Assessment, by Public and Nonpublic School Sessions: 2011
| Statistic | Type of school1 | Block W |
|---|---|---|
| † Not applicable. 1 Nonpublic school sample includes only private and Catholic schools. NOTE: The "weighted average item score" of polytomous items are standardized to have a scale of 0 to 1 so they are comparable to dichotomously scored items. The "weighted proportion of students attempting last item" is equal to 1- (percent not responding to last item /100). 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), 2011 Writing Assessment. |
||
| Number of scaled items | † | 22 |
| Unweighted sample size | Public | 22,100 |
| Nonpublic | 2,100 | |
| Weighted average item score | Public | .48 |
| Nonpublic | .56 | |
| Weighted average polyserial | Public | .68 |
| Nonpublic | .92 | |
| Weighted alpha reliability | Public | † |
| Nonpublic | † | |
| Weighted proportion of students attempting last item | Public | † |
| Nonpublic | † | |
Last updated 05 January 2016 (GF)