Research Methods Experimental Research Method Versus Correlational Research

Research Methods Experimental Research Method Versus Correlational Research Method

Experimental Method • Experiments are carefully controlled experiments that can show a causal relationship between variables • Contains an independent variable and a dependent variable

Experimental Method • Hypothesis = expressing a relationship between 2 variables: • Independent variable = the variable being manipulated to try to cause a change • Dependent variable = depends on the independent variable • A change in the independent variable will produce a change in the dependent variable

Example • The hypothesis (expression of a relationship between two variables) that playing violent video games makes people more likely to have a positive attitude toward real-life violence • What is the independent variable? • What is the dependent variable?

• Independent variable = playing violent video games (the hypothesis suggests that a change in playing violent video games will result in a change in attitude). • Dependent variable = the attitude toward violence (depends on playing violent video games)

Operational Definitions of Variables • How are you measuring the variables? • Example: What video games are considered violent? What attitudes are considered positive toward / favoring violence?

Experimental Method: Controlling for Confounding Variables • Confounding variable = any difference other than the independent variable that may affect the dependent variable • Divide into experimental and control groups (assign participants to conditions) to control for confounding variables

Experimental v. Control Group • Experimental group = the one that receives the treatment from the independent variable • Control group = does not get any of the independent variable • Example: experimental group = plays violent video games; control group = does not play violent video games

Correlational Studies • Investigate the same variables as experimental studies, but do not use the terminology independent and dependent variable because do not reveal cause-effect relationships

Correlational Studies • Do not divide participants into separate groups based on the independent variable • Most commonly use surveys to obtain data • Easier, but cannot control for confounding variables like in an experimental study

Correlational Studies • Can only predict the relationship between two variables! • Cannot attribute causation! • Ex. cannot say that playing violent video games causes people to have positive attitudes toward violence

Correlational Studies and Predictions • Positive correlation = one variable increases as other variable increases (positive correlation) • Negative correlation = one variable decreases as other increases • No relationship between variables = zero / no correlation

Experimental Studies and Cause • An experimental study can state that the independent variable causes dependent variable to change…ex playing violent games causes more positive attitudes about violence