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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 4 Mathematics Combined National and State Main Assessment: 2007

NAEP Technical DocumentationProportion of variance of the group-defining contrasts accounted for by the principal components used in the population-structure model, grade 4 mathematics 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 Mathematics Assessment.
All contrasts 1490 0.90 0.60 1.00 22 118 476 451 423
Student questionnaire 92 0.89 0.63 0.99 1 14 23 26 28
Major reporting variables 118 0.93 0.64 1.00 1 5 23 31 58
Interactions between reporting variables 437 0.91 0.60 0.99 10 28 113 148 138
Teacher questionnaire 350 0.91 0.71 0.99 0 17 93 118 122
School questionnaire 230 0.89 0.71 0.99 0 10 107 84 29
NIES questionnaire 217 0.85 0.63 0.99 10 42 104 34 27
SD/ELL questionnaire 46 0.92 0.76 0.99 0 2 13 10 21

Last updated 24 June 2010 (GF)

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