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Table of Contents | Search Technical Documentation | References
NAEP Analysis and Scaling → Estimation of Population and Student Group Distributions → Examining the Population-Structure Models Used in NAEP → Proportion of Variance Accounted for By Principal Components Used in NAEP Population-Structure Models → Proportion of Variance of the Group-Defining Contrasts Accounted for by the Principal Components Used in the Population-Structure Model, Grade 8 U.S. History National Main Assessment: 2006
| Type of contrast | Number of contrasts | Mean | Minimum | Maximum | Number of contrasts by proportion1 of variance explained | ||||
|---|---|---|---|---|---|---|---|---|---|
| 0.00 - 0.70 | 0.70 - 0.80 | 0.80 - 0.90 | 0.90 - 0.95 | 0.95 - 1.00 | |||||
| 1 (Total Variance – Residual Variance)/Total Variance, where Total Variance consists of both sampling and measurement error variance. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2006 U.S. History Assessment. |
|||||||||
| All contrasts | 1071 | 0.90 | 0.60 | 0.99 | 11 | 47 | 427 | 344 | 242 |
| Student questionnaire | 165 | 0.89 | 0.60 | 0.99 | 5 | 17 | 45 | 58 | 40 |
| Major reporting variables | 60 | 0.92 | 0.81 | 0.99 | 0 | 0 | 27 | 5 | 28 |
| Interactions between reporting variables | 495 | 0.91 | 0.64 | 0.98 | 6 | 18 | 132 | 194 | 145 |
| Teacher questionnaire | 218 | 0.88 | 0.77 | 0.98 | 0 | 12 | 115 | 70 | 21 |
| School questionnaire | 133 | 0.88 | 0.81 | 0.98 | 0 | 0 | 108 | 17 | 8 |
Last updated 19 November 2009 (GF)
