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Computing School-Level Replicate Base Weights for the 2004 Assessment

For the 2004 NAEP, the calculation of school-level replicate base weights SCH_BWTjs(r), r = 1,..., 62, were calculated as follows:

SCH underscore BWT subscript js, into bracket r subscript 2, bracket closes, equals left brace 3 rows, 3 column matrix,row 1 column 1 is: 2 times SCH underscore BWT subscript js, row 1 column 2 is: for js is an element of R subscript jr, row 1 column 3: U subscript js equals 1.

where

  • SCH_BWTjs is the school base weight for school s in primary stratum j,

  • Rjr is the set of schools within the r-th replicate stratum for primary stratum j, and

  • Ujs is the variance unit (1 or 2) for school s in primary stratum j.

For schools in replicate strata comprising three variance units, two sets of school-level replicate base weights were computed (see replicate variance estimation for details): one for the first replicate r1 and another for the second replicate r2. The two sets of school-level replicate base weights SCH_BWTjs(r1), r1 = 1,..., 62, and SCH_BWTjs(r2), r2 = 1,..., 62, were calculated as described below.  

SCH underscore BWT subscript js open paren r subscript one close paren equals open paren one point five times SCH underscore BWT subscript js for js is an element of cap R subscript jr subsubscript one and cap U subscript js equals one close paren or equals open paren one point five times SCH underscore BWT subscript js for js is an element of R subscript jr subsubscript one and cap U subscript js equals two close paren or equals open paren zero for js is an element of R subscript jr subsubscript.

 

SCH underscore BWT subscript js, into brackets r subscript 2 bracket closes, equals left brace 4 row 3 column matrix, row 1 column 1 is: 1.5 times SCH underscore BWT subscript js, row 1 column 2 is: for js is an element of R subscript jr subscript 2, row 1 column 3 is: U subscript js equals 1, row 2 column 1 is: 0, row 2 column 2 is: for js is an element of R subscript jr subscript2, row 2 column 3 is: U subscript js equals 2, row 3 column 1 is: 1.5 times SCH underscore BWT subscript js, row 3 c.

 


Last updated 05 November 2009 (GF)

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