Ch. 2

Critical thinking

Assessing claims or assertions and making judgments based on evidence.


A prediction stated as a testable proposition, usually in the form of an if-then statement.

Operational definition

Statement of the specific methods used to measure a variable. See study guide for example.


Specific factors or characteristics that are manipulated and measured in research.


Numbers that represent research findings and provide research for conclusions.


Cohesive cluster of explanations of behavior and mental processes, theories are not definitive.

Naturalistic observation

Method of gathering descriptive information, involves watching behaviors of interest, without interfering, as they occur in their natural environments.

Case studies

Used to collect descriptive data through the intensive examination of a phenomenon in a particular individual, group or situation.



Correlational studies

A research method that examines relationships between variables in order to analyze trends in data, among other things to suggest new hypotheses.



Experimental group

Receives the independent variable in an experiment.

Control group

Provides a baseline for comparison to the experimental group and does not receive the independent variable.

Independent variables

Manipulated or controlled by the researcher in an experiment.

Dependent variables

Behaviors or mental processes affected by the independent variable. They are observed and measured before and after the administration of the independent variable.

Confounding variables

Factors affecting the dependent variable in an experiment instead of or along with the independent variable. See study guide for examples.

Random variables

Uncontrolled factors that could affect the dependent variable in an experiment instead of or along with the independent variable.

Random assignment

An attempt to try to minimize effects of random variables by distributing them randomly across groups.


Butt**** melody jab.

Experimenter bias

When a researcher inadvertently encourages subjects to respond in a way that supports his hypothesis.

Double-blind design

Neither the experimenter nor the participants know has received the independent variable.


A procedure used to choose subjects for research. Ideally, the participants chosen should be representative of the population being studied.

Representative samples

Samples of participants whose characteristics fairly reflect the characteristics of other people in that group.

Random samples

Groups of subjects selected from the population of interest. A population is random only if each person in the population has an equal chance of being selected. If not, it is a biased sample.

Behavioral genetics

Explores the impact of genetics and environmental factors in differences in the behavioral tendencies of groups.

Descriptive statistics

Summarizes a set of data. Examples of descriptive stats are measures of central tendency.

Inferential statistics

Used to judge the meaning of data.

Mean, median, mode, range

Average, divides set of data in two, most frequently occurring number, subtracting lowest data from highest data


Indicaation of the relationships between two variables (x and y). The degree to which x relates to y.

Correlation coefficient

Statistic, represented by r that summarizes the strength and direction of a relationship between two variables.

Statistically significant

An indication that the group differences or correlation is larger than would occur by chance.