Weighted School Average with Weights

Weighted average in Brazilian schools: rule and example

Most Brazilian schools weight each subject by its credits (carga horária or créditos): MP = Σ(nota·cr) / Σcr. As an example, take Portuguese 5 credits with grade 7 and Math 5 credits with grade 8, giving MP = (5·7 + 5·8) / (5+5) = (35+40)/10 = 7.5. The LDB (Lei 9.394/1996) sets no single national rule for averages. It leaves that to each school's regimento and to the state education systems. A few schools just average the bimesters arithmetically. Others weight the assessments (tests, projects, attendance) or load the final exam more heavily. Credit-weighted averages are the norm in technical schools and higher education.

Applications

Ensino fundamental and médio: most schools build the annual average across the bimesters, sometimes giving the last bimester extra weight. ENEM: scores run on Item Response Theory (TRI), which already weights questions by difficulty, discrimination and guessing parameters. That makes it a weighted scheme under the hood. Supletivo / EJA: regulated by Resolução CNE/CEB 3/2010 and state norms, it works from module averages and usually treats attendance as a separate requirement. Vestibular: plenty of universities weight subjects by course, say a higher weight for math in engineering.

FAQ

Why use credits as weights? More hours mean a bigger slice of the school year and a heavier workload, so that subject deserves more pull on the average.

Is there a fixed passing average? No. Each school's regimento sets it. On a 0–10 scale, 6.0 and 7.0 are the usual cutoffs.

What if I have zero credits? A subject with zero credits stays out of the average. Some optional activities (atividades complementares) behave this way.