What is the difference between a categorical variable and a quantitative variable?
Think of an example of each. A categorical variable varies in type or kind and a quantitative variable varies in degree or amount. An example of the former is gender, and an example of the latter is class size. 2.4. Why is experimental research more effective than nonexperimental research when a researcher is interested in studying cause and effect? Strong experimental research designs (i.e., the best experiments) include both manipulation and random assignment. Manipulation is an action taken by the researcher in the world (e.g., providing a treatment to one group and a control condition to another group); manipulation allows us to see a manipulation first, and then observe the outcome or result of the manipulation. Random assignment makes the groups similar on ALL extraneous variables at the beginning of the experiment; hence, the only difference between the groups will be the level of independent variable received, allowing the differences observed after the experiment is completed
