NAEP Analysis and Scaling - Block-Level Descriptive Statistics as Defined After Scaling, Grade 8 Mathematics Combined National and State Assessments, by Public and Nonpublic School Sessions: 2011

Table of Contents | Search Technical Documentation | References

NAEP Analysis and Scaling → Initial Activities → Classical Item Analysis → Block-Level Descriptive Statistics as Defined After Scaling, Grade 8 Mathematics Combined National and State Assessments, by Public and Nonpublic School Sessions: 2011

NAEP TECHNICAL DOCUMENTATIONBlock-level descriptive statistics as defined after scaling, grade 8 mathematics combined national and state assessments, by public and nonpublic school sessions: 2011
Statistic	Type of school¹	Block M3	Block M4	Block M5	Block M6	Block M7	Block M8	Block M9	Block M10	Block M11	Block M12
† Not applicable. ¹Nonpublic school sample includes only private and Catholic schools. NOTE: The "weighted average item score" of polytomous items are standardized to have a scale of 0 to 1 so they are comparable to dichotomously scored items. The "weighted proportion of students attempting last item" is equal to 1- (percent not responding to last item /100). 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), 2011 Mathematics Assessment.
Number of scaled items	†	15	14	15	16	16	15	15	15	17	17
Unweighted sample size	Public	32,800	32,900	32,800	32,900	32,800	32,700	32,900	32,800	33,000	32,900
Unweighted sample size	Nonpublic	1,600	1,600	1,700	1,700	1,700	1,600	1,600	1,700	1,700	1,700
Weighted average item score	Public	.47	.44	.46	.52	.48	.50	.50	.54	.46	.50
Weighted average item score	Nonpublic	.53	.51	.51	.58	.53	.58	.56	.60	.53	.57
Weighted average polyserial	Public	.62	.65	.53	.65	.58	.62	.65	.61	.58	.60
Weighted average polyserial	Nonpublic	.61	.64	.54	.61	.56	.62	.63	.59	.56	.60
Weighted alpha reliability	Public	.76	.78	.70	.80	.73	.78	.77	.77	.78	.78
Weighted alpha reliability	Nonpublic	.75	.77	.70	.76	.72	.77	.75	.72	.75	.77
Weighted proportion of students attempting last item	Public	.91	.94	.83	.92	.96	.96	.96	.87	.87	.96
Weighted proportion of students attempting last item	Nonpublic	.95	.97	.89	.95	.98	.98	.99	.87	.94	.99

Last updated 06 October 2020 (ML)

Printer-friendly Version