To better understand the difference between the dependent and independent variables, read through the following scenarios and label the DV and IV. The answers to each scenario are listed at the bottom of the page. Good luck!

1. A psychologist administers injections of male hormones to several monkeys and notes that by comparison to control animals they display more aggressive acts in the testing situation. What is the DV? What is the IV?

2. An educational psychologist finds no differences in the achievement scores on a math test of students who have, or have not, been exposed to a special math-education program. What is the DV? What is the IV?

3. An experimenter administers 4 levels of a drug (0mg, 5mg, 10mg, and 15mg) to his participants and then records the amount of time that it takes each participant to complete a puzzle. What is the DV? What is the IV?

4. A professor has designed a new style of therapy to treat depression and she would like to conduct a study to determine its effectiveness. She decides to divide her participants into three groups: those receiving no therapy, those receiving the standard therapy, and those receiving the new therapy she developed. She administers a depression scale to all participants both before and after the study has been completed. She then compares the scores of the participants to one another. What is the DV? What is the IV?

1. The DV in this scenario is the number of aggressive acts. The IV is the male hormone. The level of male hormone is being manipulated by the experimenter, thus, it is the independent variable (the variable under the experimenter's control). This variable is the one that the experimenter suspects is responsible for the behavior under investigation.

2. The DV in this case is the math test scores of the students. This varies due to what type of educational environment the child was exposed to. That means that the type of math-education program the child received is the IV.

3. The experimenter manipulates the drug level. Since this variable is under the experimenter's control, it is the IV. The experimenter thinks that the differing level of drug will effect the behavior of his subjects. That's why this is the IV. The DV is the time that it takes to complete the puzzle. It happens as a result of how much drug each subject gets.

4. The IV is the type of therapy that the participants receive. The participants are being exposed to different types of therapy and the experimenter thinks that this will have an effect on their depression test scores. That means that the depression test score is the DV.

If you have any questions about this exercise, please swing by my office and ask! Thanks.