Short answer
Music builds musical skill, but passive listening does not guarantee a general-IQ increase.
What affects it
Test quality, age, health, language, education, motivation, environment, and purpose all matter.
An average study effect cannot predict one person exactly.
Guidance
Use adequate sleep, quiet conditions, accommodations, and a suitable instrument.
For children, health, disability, or high-stakes decisions, consult a qualified professional.
COMMON QUESTIONS