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Behavioral Research Chapter Four Studying Behavior.

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1 Behavioral Research Chapter Four Studying Behavior

2 Introduction Examine the basic issues and concepts necessary for understanding behavioral research. Look at the nature of variables, including measurement, types of relationships, and general methods for studying these relationships.

3 Variable- (def) any event, situation, behavior or individual characteristic that has two or more levels or values on which they can vary. Four General Categories of Variables  Response Variables  Situational Variables  Participant (Subject) Variables  Mediating Variables

4 Operational Definitions of Variables operationally definition  defines a concept by specifying precisely how the concept is measured or manipulated in a particular study.

5 How does it help us to operationally define our variables?  Defining an abstract term helps you to determine if your study (your focus) is too vague or not.  Having operationally defined our variables also helps us to communicate our ideas to others.

6 Relationships Between Variables Four most common relationships found in research are:  Positive liner relationship- increases in the values of one variable are accompanied by increases in the values of the second variable.  Negative linear relationship- Increases in the values of one variable are accompanied by decreases in the values of the other variable.  Curvilinear relationship Increases in the values of one variable are accompanied by both increases and decreases in the values of other variables.  No relationship- When there is no relationship between the two variables the graph is a straight line.

7 Correlational coefficient  (def) a numerical index of the strength of the relationship between variables.  When variables are highly correlated, this indicates there is little deviation in the general pattern of the data.  When two variables are weakly correlated, there are either many Participants who deviate from the general pattern of the data or the two variables don’t effect each other that strongly.

8 Nonexperimental vs. Experimental Methods  Nonexperimental method  relationships are studied by making observations or measures of the variables of interest.  When the two variables vary together---we say that they are correlated.  While we can say that there is a relationship between the two variables, we cannot say we can determine causality.  CORRELATION DOES NOT IMPLY CAUSATION!!

9 Problems with Non-Experimental Method Direction----cannot tell which variable causes the other. Third Variable problem: There may be a relationship between the two variables because some other variable causes both. (also called confounding variables).

10 Experimental method  Involves direct manipulation and control of variables.  The researcher manipulates the variable of interest and then observes (measures) the response.  Because one variable is manipulated while the other is measured, researchers can now comment about the direction of cause and effect.  The experimental method helps to eliminate the ambiguity found in the results

11 Extraneous variables  variable that interferes with the results, making it impossible for the researcher to draw meaningful conclusions about the effect of the variables. Experimental Control-with experimental control all extraneous variables are kept constant, and therefore cannot be responsible for the results of the experiment. Randomization- The experimental method ensures that extraneous variables, in which control would be difficult, are equalized through random assignment.

12 Independent and Dependent Variables Independent variable  what’s manipulated by the experimenter—the variable that is considered to be the cause. Dependent variables  Ps’ response, or what is measured—the variable that is the effect of the dependent variable.

13 Two Kinds of Independent Variables Manipulated I.V. Non-Manipulated I.V. Constant  a variable that is held constant, in order to prevent it from varying, and possibly affecting the outcome of the experiment.

14 Evaluating Research-Three Validities Construct Validity  Internal validity  External validity 

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