Board Certified Behavior Analyst (BCBA) Practice Test 2026 – Comprehensive All-in-One Guide to Exam Success!

The correct choice is the level of noise. In an experimental context, the dependent variable is the outcome that researchers measure to assess the effect of varying conditions, which in this case involves different music conditions on the school bus. By measuring the level of noise, the researcher can determine how the presence or type of music influences the overall noise levels. This relationship allows for an evaluation of the impact of independent variables, such as music type, on the dependent variable.

The other choices serve different purposes in the experimental design. The type of music played is an independent variable—it's what you manipulate in the experiment to observe any changes in noise levels. The number of children present and the duration of the testing period are also variables that could affect the noise level but are not the primary focus or outcome being measured in this scenario.