
case study
intensive investigation of the behavior & mental processes associated with a specific person or situation

experimental condition/experimental group
condition of an experiment that exposes participants to the treatment

singleblind procedure
research design in which participants don't know whether they are in the experimental group or control group

independent variable
factor the researcher manipulates in a controlled experiment (the cause)

mode
measure of central tendency for distribution, score that occurs more often than any other

range
the difference between the highest & lowest values in a frequency distribution

controls
constraints the experimenter places on the experiment to ensure each subject has the same exact conditions

median
measure of central tendency for a distribution score that seperates upper half of scores from lower half

expectancy bias
researcher allowing his or her expectations to affect the outcome of a study

doubleblind study
experimental procedure in which both researchers & participants are uninformed about the nature of the independent variable being administered

replicate
repetition of the methods used in a previous experiment to see whether the same methods will yield the same results

survey
questions are asked to subjects, can't be skewed or biased towards an answer

control condition/control group
condition of an experiment that contrasts with the experimental condition & serves as a comparison for evaluating the effect of the treatment

histogram
bar graph depicting a frequency distribution, height of barsfrequency of a group of scores

crosssectional study
study when a representative cross section of the population is tested or surveyed at one specific time

longitudinal study
type of study where one group of subjects is followed & observed for an extended period of time (years)

hypothesis
prediction how two or more factors are likely to be related or the outcome of a scientific study, testable idea

scientific method
fivestep process for empirical investigation of a hypothesis under conditions designed to control biases & subjective judgments

mean
measure of central tendency, used to describe a set of datacalculated by adding all scores and dividing by number of scores

dependent variable
the behavior or mental process that is measured in an experiment or quasiexperiment (effect)

personal/observer bias
researcher allowing personal beliefs to affect outcome of a study

significant difference
psychologists accept a difference between groups as "real" when the probability is 5%

variability
spread or dispersion of a set of research data or distribution

confounding/extraneous variable
variables that have an unwanted influence on the outcome of an experiment

correlational study
type of research that is mainly statistical in nature (determines the relationship between 2 varibales)

random sample
sample group of subjects selected by chance (without biased selection techniques)

illusory correlation
perception of a relationship where none exists

experiment
research where researcher controls all the conditions & direct manipulates the conditions & independent variable

correlational coefficient
number between 1 & +1 expressing the degree of relationship between two variable

inferential statistics
statistical techniques used to asses if the results of a study are reliable or if they are simply the result of chance

correlation
relationship between variables, where changes in one variable are reflected in changes in the other variable

standard deviation
measure of variability that indicates the average difference between the scores and their mean

representative sample
sample obtained so that it reflects the distribution of important variables in the larger population where the researchers are interested

frquency distribution
summary chart, showing how frequently each of the various scores in a set of data occurs

percentile score
percentage of scores at or below a particular score

quasiexperiment
measurement of DV when random assignment to groups is not possible

naturalistic observation
research method where the subjects are observed in their natural environment

operational definition
description of the specific procedure used to determine the presence of a variable, exact operations

normal distribution
bellshaped curve, describing the spread of a characteristic throughout a population

descriptive statistics
statistical procedures used to describe characteristics & responses of groups of subjects

cohortsequential study
research method where a cross section of the population is chosen then each cohort is followed for a short period of time

placebo effect
experimental resuls caused by expectations alone

random assignment
division of the sample into groups so that every individual has an equal chance of being put in any group or condition

