Presentation of data

Experimental research design aims to test hypotheses about causal relationships. It involves manipulating an independent variable and observing its effect on a dependent variable under controlled conditions. True experimental designs have three key features - manipulation, control, and randomization. Manipulation means consciously controlling the independent variable. Control involves using a control group to account for extraneous variables. Randomization ensures subjects are randomly assigned to conditions. Common true experimental designs include post-test only, pretest-posttest, Solomon four-group, factorial, randomized block, and crossover designs. While powerful for establishing causation, experimental research also has limitations for studying humans.