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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 12 Mathematics National Main Assessment: 2009

NAEP Technical DocumentationProportion of variance of the group-defining contrasts accounted for by the principal components used in the population-structure model, grade 12 mathematics national main assessment: 2009
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 0.95 - 1.00
1(Total Variance – Residual Variance)/Total Variance, where Total Variance consists of both sampling and measurement error variance.
NOTE: 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), 2009 Mathematics Assessment.
All contrasts 1,655 0.90 0.60 0.99 25 62 687 497 384
Student questionnaire 331 0.88 0.60 0.99 13 33 113 105 67
Major reporting variables 73 0.92 0.78 0.99 0 2 27 17 27
Interaction between reporting variables 528 0.91 0.62 0.99 12 23 123 154 216
School questionnaire 683 0.89 0.82 0.99 0 0 415 205 63
SD/ELL questionnaire 40 0.91 0.78 0.99 0 4 9 16 11
Last updated 05 January 2016 (GF)
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