Identifying Variables
Let’s work on extraneous variables, confounding variables, and representative samples. Identify any confounding variable(s) in the following studies and comment about whether the sample is representative of the population of interest. Look for confounding variables that are obviously present in the study. . . . avoid speculating about items that are not mentioned.
A. You are studying the effects of wording of a survey question on response to the survey. You randomly assign 50 people to group A and 50 people to group B. You read a survey to group A; all of the questions include the word “not”. Your assistant reads a survey to group B; all of the questions are the same but have been reworded to eliminate the word “not” (note that the meaning of the questions is exactly the same in both groups; just the wording is different). You compare the response to the survey between the two groups. The IV is wording of the survey questions and the DV is the score on the survey.
B. You want to know whether most people process information more easily when it is presented orally vs when it is presented in written form. The participants are students in a marching band course. You administer the same quiz twice to each participant; first the quiz administered orally; a week later the same quiz is administered in written form. You find that most people make fewer mistakes when the quiz was presented in written form. (The IV is the format of the quiz; the DV is score on the quiz.)





