empiricism
scientific method
theories
hypothesis
empirical method
operational definition
construct validity
power
reliability
demand characteristics
naturalistic observation
observer bias
double-blind study
population
sample
frequency distribution
normal distribution
mode
mean
median
range
standard deviation
variable
correlation
correlation coefficient (r)
natural correlation
third-variable problem
experimentation
manipulation
independent variable
dependent variable
self-selection
random assignment
internal validity
external validity
case method
random sampling
replication
Type I error
Type II error
informed consent
debriefing