Variable
something that varies (e.g. voter turnout)
theory
tentative conjecture about the causes of some phenomenon of interest
hypothesis
theory-based statement about a relationship that we expect to observe
null hypothesis
theory-based statement about what we would expect to observe if our theory were incorrect.
hypothesis testing
process in which scientists evaluate systematically collected evidence to make a judgment of whether the evidence favors their hypothesis or favors the corresponding null hypothesis.
empirical
based on observations of the real world
paradigm
shared assumptions and accepted theories
normal science
state of research under an accepted paradigm
paradigm shift
idea that breaks a current paradigm
variable label
description of what the variable is
variable values
denominations in which the variable occurs (e.g. years, days, hours).
theory
conjecture that the independent variable is causally related to the dependent variable
independent variable
variable that helps explain or influence change in a dependent variable
dependent variable
variable that measures an outcome of a study
causal explanation
An answer to the question of a theory, "Why do you think that this independent variable is causally related to this dependent variable"?
operationalize
to measure variables
positive relationship
relationship for which higher values of the independent variable coincide with higher values of the dependent variable.
negative relationship
relationship for which higher values of the independent variable coincide with lower values of the dependent variable
model
a simplified description of a complex entity or process
covariation
term used to describe a situation in which two variables vary together
causation
direct cause-and-effect link between the variables
correlation
r, which measures the direction and strength of the linear relationship between two quantitative variables
normative statements
statements about how the world ought to be
parsimonious
describing a simple theory. A parsimonious theory is more appealing.