Theory- a scientific theory is a logical explanation for all the relevant data or facts scientists have observed regarding certain natural phenomena: must be testable and refutable. Hypothesis- a statement that proposes the existence of a relationship between variables, typically as a tentative explanation for cause and effect, hypotheses are often designed to be tested by research. Basic research- research that tests theories or hypotheses: research done for the love of science. Applied research- research to solve a problem: research performed is applied to everyday problems, clinical and counseling psychology, business, workplace applications. Replication studies- research conducted for the purpose of verifying previous findings: backbone of good science. Important because the results of a study can vary considerably depending on experimental conditions and the research method used. Case study- method of research that involves in-depth study of one or more subjects who are examined individually using direct observation, testing, experimentation, and other methods.