- Surveys & Programs
- Data & Tools
- Fast Facts
- News & Events
- Publications & Products
- About Us
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 the 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, Age 17 Mathematics Long-Term Trend Assessment: 2008
| 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. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2008 Mathematics Long-Term Trend Assessment. |
|||||||||
| All contrasts | 644 | 0.90 | 0.56 | 0.99 | 17 | 55 | 168 | 203 | 201 |
| Student questionnaire | 91 | 0.87 | 0.60 | 0.99 | 4 | 17 | 27 | 21 | 22 |
| Major reporting variables | 61 | 0.90 | 0.67 | 0.99 | 1 | 8 | 16 | 13 | 23 |
| Interactions between reporting variables | 456 | 0.91 | 0.56 | 0.99 | 12 | 25 | 108 | 160 | 151 |
| SD/ELL questionnaire | 36 | 0.87 | 0.74 | 0.97 | 0 | 5 | 17 | 9 | 5 |
Last updated 14 December 2011 (GF)
