Psych Ch 2
operational definition
a definition that provides an objective description of how a variable is going to be measured and observed in a particular study
independent variable
a manipulated experimental factor, the variable that the experimenter changes to see what its effects are
confederate
a person who is given a role to play in a study so that the social context can be manipulated
random sample
a sample that gives every member of the population an equal chance of being selected
hypothesis
a testable prediction that derives logically from a theory
double-blind experiment
an experimental design in which neither the experimenter nor the participants are aware of which participants are in the experimental group and which are in control group until the results are calculated
demand characteristics
any aspects of a study that communicate to the participants how the experimenter wants them to behave
variable
anything that can change
case study
case history, an in-depth look at a single individual
placebo
in a drug study, a harmless substance that has no physiological effects, given to participants in a control group so that they are treated identically to the experimental group except for the active agenda
research participant bias
in an experiment, the influence of participants' expectations, and of their thoughts about how they should behave, on their behavior
random assignment
researchers' assignment of participants to groups by chance, to reduce the likelihood that an experiment's results will be due to preexisting differences between groups
longitudinal design
special kind of systematic observation, used by correlational researchers, that involves obtaining measures of the variables of interest in multiple waves over times
third variable problem
the circumstance where a variable that has not been measured accounts for the relationship between two other variables 3rd variables also known as confounds
external validity
the degree to which an experimental design actually reflects the real-world issues it is supposed to address
internal validity
the degree to which changes in the dependent variable are due to the manipulation of the independent variable
population
the entire group about which the investigator wants to draw conclusions
experimenter bias
the influence of the experimenter's expectations on the outcome of research
naturalistic observation
the observation of behavior in a real-world setting
dependent variable
the outcome - the factor that can change in an experiment in response to changes in the independent variable
control group
the participants in an experiment who are as much like the experimental group as possible and who are treated in every way like the experimental group except for a manipulated factor, the independent variable
experimental group
the participants in an experiment who receive the drug or other treatment under study - those who are exposed to the change that the independent variable represents
placebo effect
the situation where participants expectations, rather than the experimental treatment, produce an experimental outcome
validity
the soundness of the conclusions that a researcher draws from an experiment
sample
the subset of the population chosen by the investigator for study
theory
a broad idea or set of closely related ideas that attempts to explain observations and to make predictions about future observations
experiment
a carefully regulated procedure in which the researcher manipulates one or more variables that are believed to influence some other variable
correlational research
research that examines the relationships between variables, whose purpose is to examine whether and how two variables change together
