NAEP Analysis and Scaling - Proportion of Variance of the Group-Defining Contrasts Accounted for by the Principal Components Used in the Population-Structure Model, Grade 8 Science Combined National and State Main Assessment: 2005

NAEP Technical DocumentationProportion of variance of the group-defining contrasts accounted for by the principal components used in the population-structure model, grade 8 science combined national and state main assessment: 2005
Type of contrast	Number of contrasts	Mean	Minimum	Maximum	Number of contrasts by proportion¹ of variance explained
Type of contrast	Number of contrasts	Mean	Minimum	Maximum	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), 2005 Science Assessment.
All contrasts	1,184	0.90	0.59	1.00	32	95	323	356	378
Student questionnaire	160	0.88	0.59	0.99	6	20	50	50	34
Major reporting variables	97	0.93	0.74	1.00	0	3	22	24	48
Interactions between reporting variables	636	0.90	0.59	0.99	16	43	168	180	229
Teacher questionnaire	105	0.89	0.62	0.99	9	10	24	30	32
School questionnaire	186	0.89	0.69	0.98	1	19	59	72	35

Last updated 13 May 2009 (RF)