Final answer:
Researchers use experimental methods to establish cause-effect relationships and correlational methods to predict events by examining the association between variables.
Step-by-step explanation:
Researchers use experimental techniques to determine cause-effect relationships and correlational techniques to predict events. Experimental research involves the manipulation of variables to test a hypothesis in a controlled setting, allowing for the establishment of a causal relationship. On the other hand, correlational research examines the relationship or association between two variables but does not necessarily imply causation. An example of experimental research might be manipulating the amount of a specific nutrient in a plant's diet to see the effect on growth. In contrast, correlational research might look at the relationship between the number of fast-food outlets in a neighborhood and the prevalence of obesity, while considering other factors such as ethnicity, income, and access to parks through regression analysis.