Bai is conducting a study on learning. when she manipulates an independent variable, it is possible that some other factor, such as noise in the hall, can affect learning in one of the groups but not in the other. this possibility reflects the presence of:

An extraneous variable.

An extraneous variable is an external and unwanted factor that distorts the results in a research experiment. It can lead to a variable other than the independent variable (IV) resulting in an outcome or dependent variable (DV). In Bai's study, noise in the hall is an extraneous variable that might affect learning outcomes of one group of her study.