physics chapter 11 mcat

positive controls

ensure that a change in the dependent variable occurs when expected/It's used to verify that the experiment is capable of producing a positive result and that the experimental setup is working correctly.

negative controls

ensure that no change in the dependent variable occurs when none is expected/SUGAR PILL

cohort studies

record exposures throughout time and then asses the rate of a certain outcome

cross sectional studies

assess both exposure and outcome at the same point in time

case control studies

assess the outcome status and then assess for exposure history

selection bias

the sample differs from the population (most often seen in human studies)

detection bias

arises from educated professionals using their knowledge in an inconsistent way by searching for an outcome disproportionately in certain populations

hawthorne effect

results from changes in behavior -by the subject, experimenter, or both- that occurs as result of the knowledge that the subject is being observed

confounding

correlation does not equal causation

an error in data analysis that is results from a common connection of both the dependent and independent variables to a third variable