NAEP Analysis and Scaling - Overall Descriptive Statistics for Item Blocks as Defined After Scaling, Grade 8 Visual Arts National Main Assessment: 2008

NAEP Analysis and Scaling → Initial Activities → Classical Item Analysis → Overall Descriptive Statistics for Item Blocks as Defined After Scaling, Grade 8 Visual Arts National Main Assessment: 2008

NAEP Technical DocumentationOverall descriptive statistics for item blocks as defined after scaling, grade 8 arts (visual arts) assessment: 2008
Statistic	Item type	Block V3	Block V4	Block V5	Block V6
† Not applicable. ¹ The "Weighted proportion of students attempting last item" is equal to 1 - (Percent not responding to last item /100). NOTE: Item statistics in this table are described on the page Blocks of Items. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2008 Arts (Visual Arts) Assessment.
Number of scaled items	Total	5	12	9	6
	Multiple choice	1	4	3	2
	Dichotomously scored constructed response	0	2	1	2
	Polytomously scored constructed response	4	6	5	2
Unweighted sample size	†	1,900	2,100	1,900	1,900
Weighted average item score	†	0.44	0.46	0.45	0.45
Weighted average polyserial	†	0.64	0.53	0.58	0.60
Weighted alpha reliability	†	0.52	0.67	0.61	0.35
Weighted proportion of students attempting last item¹	†	0.81	0.90	0.82	0.99

Last updated 28 September 2011 (JL)