What represents the dependent variable in a study examining memory test performance?

In research studies, the dependent variable is the outcome that researchers measure to see if it is affected by changes in the independent variable. In this context, the study examines memory test performance, and the percentage of errors on a memory test directly reflects individuals' performance on that test. It represents how well participants can recall or recognize information, which is precisely what the study aims to evaluate.

The treatment method used, the total number of participants, and the age of the subjects are all factors that could influence or contextualize the results of the study, but they do not serve as the primary outcome being measured. Instead, they are independent variables or contextual variables that may impact the dependent variable, but they do not represent the performance being directly assessed. The percentage of errors is the indicator of memory test performance, making it the correct choice for the dependent variable in this scenario.