The dataset includes fifth-grade cross-sectional data, focusing on students' mathematical
assessment scores as the primary outcome measure. The mathematical assessment covers 18 topics
such as number sense, properties, operations, measurement, geometry, data analysis, and algebra.
These items evaluate students' competencies in conceptual knowledge, procedural knowledge, and
problem-solving, consolidated into a single "Math score." A higher score indicates greater proficiency.
The primary predictors are household income and gender, where gender is a categorical variable.
Household income is categorized into 18 ordinal levels, ranging from $5,000 or less (level 1) to
$200,000 or more (level 18). In the analysis, the income variable is treated as a continuous variable.
The dataset removes all records with missing values and consists of 9,101 complete observations from 2,275 schools.