Answer:
Extraneous
Step-by-step explanation:
A variable may be classed an being extraneous if during an experiment, a certain variable which isn't considered as part of the experimental process poses the potential of having an effect on the experimental process and as such could have an impact on the outcome or out of the experiment. In the scenario described above, a flickering light could have a higher effect on an experiment which is aimed at concentrating in a memory task. However x since the flickering light was not supposed to be part of the variable designed for the experiment, then it is called an extraneous variable.