If extraneous variables are not controlled in an experiment, what major problem will the researcher face?
A) not having enough data to allow for valid statistical analysis
B) the results will be stated in subjective, and possibly biased terms
C) it cannot be known which variables) produced the observed results
D) not having enough participants

Question

Quizplus · Accepted Answer

Extraneous variables, if not controlled, introduce uncertainty about what is actually causing the observed outcomes. This makes it difficult to determine whether the independent variable(s) being tested are responsible for the observed effects, or if these effects are due to some other uncontrolled factor.

If Extraneous Variables Are Not Controlled in an Experiment, What