Assignment: One-Way Experimental Designs
Correlational research, which you explored in this week’s Discussion, is useful in identifying relations between two variables, but does not make assumptions regarding cause and effect among the variables because researchers did not control for outside factors. To demonstrate possible causal relations among variables, researchers will need to manipulate variables in an experimental research design.
The variable that the researcher manipulates in an experimental research design is termed the independent variable. As a researcher, one important determination you need to make is the number of independent variables involved in the study. If you manipulate one independent variable, the study would be termed a one-way experimental design.
Researchers also need to determine dependent variables. In an experimental design, the dependent variable is the measure of the effect of the independent variable. If the dependent measure reveals an effect made by an independent variable, a researcher may be able to determine cause.
Consider a study that hypothesizes that 8-year-olds who play educational computer games score higher on intelligence tests than those who do not play educational computer games. Consider how many aspects you would need to address if you were conducting the study. First, you would need to understand that the independent variable is the game-playing, whereas the dependent variable is the scores on the intelligence test.
Next, you would need to determine the levels of the independent variable. In this scenario, suppose there are three levels of play: no play, some play (4 hours a week), and frequent play (8 or more hours a week).
Additionally, you would need to determine whether the study is a between-participants design or a within-participants design (also known as a repeated-measures design). A between-participants design uses different groups for each level. A within-participants design uses the same group, and that one group repeats the experiment for each level.
In this Assignment you apply key concepts related to experimental design to a research study and analyze and interpret the outcome.