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[Institution’s Name]
Essay on Curriculum and Instruction
The Third International Mathematics and Science Study (TIMSS) is a large project that covers multiple dimensions, including cross-national testing scores, survey questionnaires, videotape studies, and curriculum analyses. Since the mid-1990s, several states and school districts across the U.S. have adopted the TIMSS benchmark to assess their condition of mathematics and science education. As a result, the score comparison becomes a focus of attention among many mathematics and science educators. Schmidt and McKnight (1998) noted, "The use of adjacent grades in the third/ fourth--and seventh/eighth-grade populations allow the estimation of differences between cross-section samples of grade pairs, which is a fair surrogate for gains that might have been measured by a true longitudinal design.”
As an innovative approach adopted in this investigation, the computing procedure should be described to facilitate verification of the statistical findings. The method is outlined here in three steps. In the first step, the following SAS codes are employed to transpose the list of variable names into a column. In the second step, a LAG function is introduced to calculate the mean score difference between adjacent rows. This function is available in both SPSS (1988) and SAS (1990). Because the item mean scores are arranged by grade and country, this operation inevitably includes score subtractions between the last record of the previous country and the first record of the next country.
In the transposed data structure, these records are linked to different items in adjacent countries. This portion of results is meaningless, since a lower grader in Japan may not necessarily score lower than a higher grader from South Africa on different test items. In the third step, a SAS command is issued to remove these redundant subtraction results across the country borders. In addition, a statement is employed to single out these items that have resulted...............
