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Table of Contents | Search Technical Documentation | References
HomeTDWNAEP Analysis and ScalingEstimation of Population and Student Group DistributionsExamining the Population-Structure Models Used in NAEPProportion of Variance Accounted for By Principal Components Used in NAEP Population-Structure ModelsProportion of Variance of the Group-Defining Contrasts Accounted for by the Principal Components Used in the Population-Structure Model, Grade 4 Reading Combined National and State Main Assessment: 2007
| 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. NOTE: NIES = National Indian Education Study; SD/ELL = Students with disabilities/English language learners. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2007 Reading Assessment. |
|||||||||
| All contrasts | 1541 | 0.90 | 0.60 | 1.00 | 20 | 121 | 496 | 467 | 437 |
| Student questionnaire | 149 | 0.90 | 0.62 | 0.99 | 1 | 7 | 59 | 53 | 29 |
| Major reporting variables | 115 | 0.93 | 0.63 | 1.00 | 1 | 4 | 19 | 37 | 54 |
| Interactions between reporting variables | 435 | 0.91 | 0.60 | 0.99 | 10 | 28 | 112 | 130 | 155 |
| Teacher questionnaire | 351 | 0.92 | 0.70 | 0.99 | 0 | 28 | 74 | 125 | 124 |
| School questionnaire | 229 | 0.89 | 0.71 | 0.99 | 0 | 10 | 113 | 79 | 27 |
| NIES questionnaire | 217 | 0.85 | 0.61 | 0.99 | 8 | 41 | 105 | 36 | 27 |
| SD/ELL questionnaire | 45 | 0.92 | 0.76 | 0.99 | 0 | 3 | 14 | 7 | 21 |
Last updated 24 June 2010 (GF)