"A stress researcher wants to look at the effect of meditation on anxiety. To do this, she creates two groups of subjects: one group receives instruction in meditation, whereas the other receives no training at all. One month later, she has subjects complete a questionnaire designed to measure anxiety and she looks to see whether there are any differences in anxiety between the two groups. In this experiment, the meditation condition (meditation vs. no meditation) would be the variable and anxiety would be the variable."