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NAEP Analysis and Scaling → Initial Activities → Classical Item Analysis → Overall Descriptive Statistics for Item Blocks as Defined After Scaling, Age 17 Mathematics Long-Term Trend Assessment: 2004
Overall descriptive statistics for item blocks as defined after scaling, age 17 mathematics long-term trend assessment: 2004
Statistic Item type Block M21 Block M22 Block M23 Block M24 Block MX51 Block MX52
Number of scaled items Total 23 22 35 35 23 22
Multiple choice 19 17 25 30 18 17
Dichotomously scored constructed response 4 5 10 5 5 5
Polytomously scored constructed response 0 0 0 0 0 0
Unweighted sample size 3,800 3,800 3,800 3,700 3,800 3,700
Weighted average item score 0.67 0.69 0.66 0.69 0.65 0.68
Weighted average polyserial 0.72 0.65 0.67 0.63 0.69 0.67
Weighted alpha reliability 0.89 0.82 0.91 0.89 0.87 0.84
Weighted proportion of students attempting last item1 0.93 0.97 0.87 0.74 0.93 0.98
† 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), 2004 Mathematics Long-Term Trend Assessment.

Last updated 06 February 2009 (GF)

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