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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 of the Group-Defining Contrasts Accounted for by the Principal Components Used in NAEP Student Group Distribution Models → Proportion of Variance of the Group-Defining Contrasts Accounted for by the Principal Components Used in the Population-Structure Model, Age 9 Reading Long-Term Trend Assessment: 2004
| Type of contrast | Number of contrasts | Mean | Minimum | Maximum | Number of contrasts by proportion1 of variance explained | ||||
|---|---|---|---|---|---|---|---|---|---|
| 0.00 - 0.70 | 0.71 - 0.80 | 0.81 - 0.90 | 0.91 - 0.95 | 0.96 - 1.00 | |||||
| 1(Total Variance – Residual Variance)/Total Variance, where Total Variance consists of both sampling and measurement error variance. NOTE: Teacher and school questionnaires were not included in the long-term trend assessments in 2004. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2004 Reading Long-Term Trend Assessment. |
|||||||||
| All contrasts | 647 | 0.90 | 0.58 | 0.98 | 5 | 29 | 240 | 284 | 89 |
| Student questionnaire | 50 | 0.86 | 0.62 | 0.97 | 3 | 10 | 17 | 17 | 3 |
| Major reporting variables | 37 | 0.89 | 0.58 | 0.97 | 1 | 4 | 8 | 12 | 12 |
| Interactions between reporting variables | 560 | 0.90 | 0.70 | 0.98 | 1 | 15 | 215 | 255 | 74 |
Last updated 13 May 2009 (RF)
