What are extraneous and operationalised dependant variables?
Variables are any factors in an experiment that can be controlled, manipulated and measured. An extraneous variable is any variable in a scientific study that is not purposefully being manipulated or measured by the experimenter. Whilst an experimenter should do all they can to prevent the occurence of these variables some are unavoidable. Extraneous variables that are present in all of the experimental conditions are a nuisance but are normally pretty harmless because any effect they have is usually the same in all conditions and thus becomes balanced out. However, an extraneous variable present in some conditions but not others can produce a bias in the results and is known as a confounding variable. For example, if I did a study on the effect of drinking coffee on memory and tested all of my participants memories at night, it wouldn’t matter too much if being tested at night meant they were tired and had slightly poorer memory because this reduction in memory ability would be presen
