|Statistic||Item type||Block U3||Block U4||Block U5||Block U6|
|† 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 (Music) Assessment.
|Number of scaled items||Total||15||17||15||15|
|Dichotomously scored constructed response||4||4||3||2|
|Polytomously scored constructed response||6||6||6||10|
|Unweighted sample size||†||2,000||2,000||1,900||1,900|
|Weighted average item score||†||0.38||0.48||0.53||0.31|
|Weighted average polyserial||†||0.54||0.51||0.55||0.51|
|Weighted alpha reliability||†||0.68||0.68||0.71||0.71|
|Weighted proportion of students attempting last item1||†||0.91||0.99||0.96||0.98|