Homework 1 (20 pts.)
Part I (6 pts.)
Experiments: Identifying Variables and Groups
In each of the examples, identify the independent variable and dependent variable as well as which participants make up the experimental group and which make up the control group.
Independent Variable = What the investigator manipulates; the particular treatment or condition the investigator is most interested in the effects of
Dependent Variable = What is measured or observed; the "data" collected in the experiment
Experimental Group = Those participants exposed to the independent variable
Control Group = Those participants treated just like the experimental group EXCEPT they are not exposed to the independent variable; the group with which the experimental group can be compared
1) Of 100 individuals with moderate depression, 50 receive 8 weeks of a new cognitive-behavioral therapy, while the other 50 are placed on a waiting list for 8 weeks. At the end of the 8 weeks all 100 are given psychological tests to assess their level of depression.
Independent Variable? (explain): The independent variable is the cognitive-behavioral therapy given to 50 of the individuals. This is the independent variable because this is what the investigator is manipulating and most interested in analyzing the effects from it.
Dependent Variable? (explain): The dependent variable is the measureable affects of the people that have taken the cognitive-behavioral therapy. This will be their level of depression after have received the therapy
Experimental Group? (explain): The experimental group is the 50 individuals that are receiving the therapy for their depression. This group is the where observable data is collected to prove whether the hypothesis is correct or not.
Control Group? (explain): The control group is the other 50 individuals that are currently on the “waiting-list” to receive the therapy. They do not receive the independent variable. The data observed from their behavior will also show if the hypothesis is correct or not.
2) A biopsychologist is studying the effects of anabolic steroids on the aggressive behavior of female rats. 24 female rats receive daily injections of a placebo (fake drug), while 24 others receive daily injections of the steroid. Round-the-clock videotapes of the communal cages of all rats allow all aggressive encounters to be counted and timed.
Independent Variable? (explain): The independent variable is the steroids given to the female rats. This is variable that can be manipulated and is the main factor that the bio psychologist wants to study the effects of.
Dependent Variable? (explain): The dependent variable is the amount of aggressive encounters that is counted while all the rats are in the cage together. This is the measureable behavior that will either deny or confirm the hypothesis of steroids causing aggressive behavior.
Experimental Group? (explain): The experimental group is the 24 rats that receive the steroids. If these rats show aggressive actions, this will prove that the steroids do cause aggressiveness.
Control Group? (explain):The controlled group is the 24 rats that receive the placebo of the steroids. The rats might think that they are receiving steroids therefore acting as those that did. Their actions will show whether the hypothesis is correct or if aggressiveness comes from something other than steroids.
3) An industrial psychologist is interested in whether lowering the temperature in a...