Chapter 1 Terms

Anecdotal Evidence: Information or evidence gathered from others or from one’s own experiences.

Case Study: An in-depth investigation of an individual person or a small group of people, often over an extended period of time.

Confounding Variable: See Extraneous Variable.

Constant: A feature or quality that always takes the same value across all situations.

Construct Validity: The extent to which there is evidence that a test measures a particular hypothetical construct.

Control Group: A group of individuals designed to serve as an accurate comparison in an experiment.

Correlation: A measure of the strength of the relationship between two variables.

Correlation Coefficient: A numerical index of the degree of relationship between two variables.

Dependent Variable: A variable that is measured in an experiment.

Descriptive Statistics: Statistics designed to describe the data collected. Includes mean, median, and standard deviation.

Double-Blind Study: Experiment in which neither the experimenter nor the participants know which group each participant belongs to.

Empiricism: The philosophical perspective that states that knowledge should be gained by direct observation of the world as it is, as opposed to rational perspectives that used logic and reason to determine how the world ought to be.

Experiment: Scientific tool used to measure the effect of one variable on another.

Experimental Group: The participants in a study who receive the manipulation in regard to the independent variable.

Experimenter Bias: Actions made by the experimenter, unintentionally or deliberately, to promote the result they hope to achieve.

Extraneous Variable: A variable that the researcher did not manipulate or measure, but that nonetheless could still affect the outcome of the experiment

Frequency Distribution: A figure that plots values of a variable on the x (horizontal) axis and the frequency with which those values were observed on the y (vertical) axis.

Hypothesis: Testable statements guided by theories that make specific predictions about the relationship between variables.

Independent Variable: A variable that is controlled or manipulated in an experiment.

Inferential Statistics: Statistics that allow us to use results from samples to make inferences about overall, underlying populations.

Interview: A research tool during which the investigator asks the participant questions, often these may be structured or semi-structured in nature.

Levels of Analysis: Different perspectives that emphasize different aspects of a research question.

Mean: Average value of a set of data.

Measures of Central Tendency: Descriptive statistical techniques for summarizing a distribution of data into a single value that represents the entire distribution.

Median: The centre value in a data set when the set is arranged numerically.

Mode: The value that appears most frequently in the set.

Naturalistic Observation: A descriptive research method in which the researcher engages observation of behaviour in real-world settings.

Normal Distribution: A distribution with a characteristic smooth, bell and symmetrical-shaped curve around a single peak.

Paradigm: A set of assumptions and ideas about what kind of research questions can be asked and how they can be answered.

Ob-ob mouse: The particular term for a mouse that is the result of a genetic mutation associated with extreme obesity in the mouse.

Operational Definition: This describes the actions or operations that will be made to objectively measure or control a variable.

Outlier: A value that lies outside (much smaller or much bigger) than most of the other values in a data set.

Participants: The persons whose behaviour is systematically studied or observed in a study or experiment.

Placebo Effect: When an individual exhibits an effect to a perceive treatment when no treatment is actually given.

Population: The full group of individuals you are seeking to understand.

Practice Effect: Improved performance over the course of an experiment due to becoming more experienced.

Psychological Test: A standardized measure of a sample of a person’s behaviour e.g. IQ test.

Questionnaire: A research tool in which a participant responds to a written list of items or questions.

Random Assignment: Assigning participants to either the experimental or control group at random to avoid any biases that may cause differences between the groups of subjects.

Random Sample: Choosing a set of subjects at random from the population being studied.

Raw Data: Data collected from a study or experiment that has yet to be assessed using statistical analyses.

Reliability: The measurement consistency of a test (or of other kinds of measurement techniques).

Replication: The repetition of a study to see whether the earlier results can be duplicated, often times by independent researchers.

Response Set: A tendency of research participants to respond to questions in a particular way that is unrelated to the content of the questions.

Sample: The subset of the population you’re interested in that you examine.

Sampling Bias: A problem that occurs when a sample is not representative of the population from which it is drawn.

Scientific Method: The formal methods, primarily the set of techniques and concepts, used to examine and answer questions of a scientific nature.

Social Desirability Bias: A tendency to give socially approved answers to questions about oneself.

Standard Deviation: A measure of the variability of a set of data, specifically the expected difference between any randomly selected datum and the mean of the set.

Statistically Significant: The condition that exists when the probability that the observed findings are due to chance is very low.

Theory: A set of statements or principles that try to relate and explain a set of observations.

Variability: The extent to which the scores in a data set tend to vary from each other and from the mean.

Variable: A feature or characteristic that is free to take on (at least two) different values.