psy chp 2

Scientific Method

the procedures by which scientists conduct research, consisting of five basic processes: observation, prediction, testing, interpretation, and communication


a set of related assumptions from which scientists can make testable predictions


a specific, informed, and testable prediction of the outcome of a particular set of conditions in a research design


the repetition of a study to confirm the results; essential to the scientific process


claims presented as scientific that are not supported by evidence obtained with the scientific method

Research design

plans of action for how to conduct a scientific study


a characteristic that changes, such as age, gender, weight, intelligence, anxiety, and extraversion


the entire group population a researcher is interested in


subsets of the population studied in a research project

Social Desirability Bias

the tendency toward favorable self-presentation that could lead to inaccurate self-reports

Descriptive Designs

study designs in which the researcher defines a problem and variable of interest but makes no prediction and does not control or manipulate anything

Case Study

a study design in which a psychologist, often a therapist, observes one person over a long period of time

Naturalistic Observation

a study in which the researcher unobtrusively observes and records behavior in the real world

Representative Sample

a research sample that accurately reflects the population of people one is studying

Correlational Designs

studies that measure two or more variables and their relationship to one another; not designed to show causation

Correlation Coefficient

a statistic that ranges from -1.0 to +1.0 and assesses the strength and direction of association between two variables


a research design that includes independent variables and random asssignment of participants to control and experimental groups or conditions

Independent Variable

a property that is manipulated by the experimenter under controlled conditions to determine whether it causes the predicted outcome of an experiment

Dependent Variable

in an experiment, the outcome or response to the experimental manipulation

Random Assignment

the method used to assign participants to different research conditions so that all participants have the same chance of being in any specific group

Experimental Group

a group consisting of those participants who will receive the treatment or whatever is predicted to change behavior

Control Group

a group of research participants who are treated in exactly the same manner as the experimental group, except that they do not receive the independent variable or treatment


a substance or treatment that appears identical to the actual treatment but lacks the active substance

Single-Blind Studies

studies in which participants do not know the experimental conditions (group) to which they have been assigned

Double-Blind Studies

studies in which neither the participants nor the researchers administering the treatment know who has been assigned to the experimental or control group

Experimenter Expectancy Effects

results that occurs when the behavior of the participants is influenced by the experimenter�s knowledge of who is in the control group and who is in the experimental group

Self-Fulfilling Prophecy

a statement that affects events to cause the predictions to become true


a research and statistical technique for combining all research results on one question and drawing a conclusion

Effect Size

a measure of the strength of the relationship between two variables or the magnitude of an experimental effect


written or oral accounts of a person�s thoughts, feelings, or actions

Behavioral Measures

measures based on systematic observation of people�s actions either in their normal environment or in a laboratory setting

Physiological Measures

measures of bodily responses, such as blood pressure or heart rate, used to determine changes in psychological state

Multiple Measurement

the use of several measures to acquire data on one aspect of behavior


Collection, analysis, interpreation, and presentation of numerical data

Descriptive Statistics

measure used to describe and summarize research data


the arithmetic average of a series of numbers


the score that separates the lower half of scores from the upper half


a statistic that represents the most commonly occurring score or value

Standard Deviation

a stastistical measure of how much scores in a sample vary around the mean


the rules governing the conduct of a person or group in general or in a specific situation�or more simply, standards of right and wrong


the explanation of the purposes of a study following data collection

Institutional Review Boards (IRBs)

organizations that evaluate research proposals to make sure research involving humans does not cause undue harm or distress

Quasi-experimental Design

research method similar to an experimental design except that it makes use of naturally occurring groups rather than randomly assiging subjects to groups