reading: experimental design

science

a human endeavor based on asking questions about the natural and physical world and answering them with measurable, verifiable evidence.

pseudoscience

a tradition that tries to explain or predict natural and physical phenomena but 1) does not rely on measurable, verifiable evidence, and 2) invokes mysterious or unnamed mechanisms rather than known physical mechanisms.

hypothesis

a proposed explanation for something that researchers have observed.

prediction

a statement of an outcome that should occur if a hypothesis is correct.

null hypothesis

a hypothesis that represents the “not” or “no-effect” contrast to the hypothesis being tested.

treatment (or experimental) group

a group that experiences experimental conditions that conform to the mechanism proposed in the hypothesis.

control group

a comparison group that represents the normal or no-treatment condition to contrast with groups that experience experimental manipulation.

controlled conditions

aspects of an experimental design that are used in both control and experimental treatments to eliminate bias among treatments and reduce influence from confounding factors.

outcome variable

the variable that is measured in an experiment or observational study. it represents a quantity that is relevant to the hypothesis being tested.