Unit 2 method of research

Hindsight bias

The tendency to believe, after learning an outcome, that one would have foreseen or predicted it.

Overconfidence

The tendency to overestimate the accuracy of one's own knowledge, beliefs, or judgments.

Experiment

A research method in which an investigator manipulates one or more independent variables to observe the effect on a dependent variable while controlling extraneous variables.

Independent variable

The factor in a study that is manipulated or altered by the experimenter to observe its effect on an outcome.

Dependent variable

The outcome factor measured by researchers to determine if it changes in response to manipulations of another variable.

Confounding variable

An unmeasured extraneous factor that varies systematically with the independent variable and influences results, obscuring cause-and-effect relationships.

Random assignment

A procedure in experiments where every participant has an equal chance of being placed into any condition, minimizing preexisting group differences.

Case study

An in-depth investigation of a single individual, group, or event to explore complex phenomena.

Naturalistic observation

A research method involving the systematic recording of behavior in its real-world environment without intervention or manipulation.

Correlation

A measure of the extent to which two variables co-vary together, allowing one to predict the other without proving causation.

Meta-analysis

A statistical technique that combines results from multiple independent studies to derive an overall conclusion or effect size.

Operational definition

A precise statement detailing the exact procedures and measurements used to define a research variable.

Falsifiable

A property of a hypothesis or theory that allows it to be inherently proven wrong through empirical testing.

Mean

The arithmetic average of a distribution, calculated by dividing the sum of all scores by the total count ($\bar{x} = \frac{\sum x}{n}$).

Median

The middle score in a distribution when data points are arranged in numerical order.

Mode

The score or value that appears most frequently in a dataset.

Range

A measure of variation computed as the difference between the highest and lowest scores in a dataset.

Normal curve

A symmetrical, bell-shaped density curve describing a distribution where most values cluster around the central average.

Skewness

A measure of asymmetry in a statistical distribution, where data tails off toward one side.

Bimodal distribution

A data distribution containing two distinct modes or prominent peaks.

Sample

A subset of individuals selected from a larger population to participate in a study.

Population

The entire group of individuals or objects about which researchers wish to draw conclusions.

Representative sample

A subgroup whose characteristics closely reflect those of the broader population from which it was selected.

Random sampling

A selection process ensuring every member of a target population has an equal probability of being chosen for a study.

Convenience sampling

A non-probability sampling method where subjects are selected based on easy availability and accessibility.

Sampling bias

A flawed selection process that yields an unrepresentative group of participants.

Generalization

The extent to which research conclusions drawn from a sample can be applied to broader populations or settings.

Experimental group

The participants in a study who are exposed to the specific treatment or variable manipulation being tested.

Control group

The baseline group in an experiment that does not receive the active treatment, used for direct comparison.

Placebo

An inactive substance or sham treatment given to control groups to isolate the psychological effects of belief in a treatment.

Single-blind procedure

An experimental setup where participants are unaware of whether they are in the treatment or control group, but researchers know.

Double-blind procedure

An experimental setup where neither the participants nor the research staff know who has received the active treatment or placebo.

Scatterplot

A graph featuring plotted points that displays the direction and strength of the relationship between two quantitative variables.

Correlation coefficient

A numerical index ranging from $-1.00$ to $+1.00$ that quantifies the strength and direction of a linear relationship.

Effect size

A quantitative measure of the magnitude or strength of an experimental outcome, commonly classified as small, medium, or large.

Statistical significance

A statistical determination that an observed research result is unlikely to have occurred by random chance, typically marked by $p < 0.05$.

Qualitative vs. Quantitative

The distinction between research gathering non-numerical descriptive data versus research collecting numerical metrics for statistical analysis.

Structured interview

A quantitative data collection method in which all respondents are asked identical, predetermined questions in the exact same order.

Likert scale

A rating scale commonly used in surveys where respondents choose from a range of ordered options to express agreement or disagreement.

Social desirability bias

The tendency of survey respondents to answer questions in a manner that will be viewed favorably by others.

Experimenter bias

Unintentional actions or subtle cues by researchers that influence participant responses or data interpretation to match hypotheses.

Peer review

The formal evaluation of scientific research by independent experts in the same field prior to publication.

Replication

Repeating a research study, often with different participants or conditions, to determine if original findings can be reproduced.

Hypothesis

A specific, testable prediction derived from a theory regarding the relationship between variables.

Directionality problem

An issue in correlational research where it is impossible to determine whether variable A causes variable B or variable B causes variable A.

Third variable problem

A limitation in correlational studies where an unmeasured external variable causes the observed association between two variables.

Survey

A research technique used to gather self-reported attitudes, opinions, or behaviors from a group via questionnaires or interviews.

Self-report bias

Distortions in data occurring when participants inaccurately, dishonestly, or selectively report their own thoughts and behaviors.

Institutional Review Board (IRB)

An administrative committee that reviews human research proposals to protect participant safety, rights, and ethical standards.

Informed consent

An ethical principle requiring researchers to inform prospective participants of study details and risks before they decide to join.

Informed assent

The agreement given by minors or vulnerable individuals who express willingness to participate alongside formal legal consent from a guardian.

Protection from harm

An ethical requirement mandating that researchers prevent physical, psychological, or emotional distress to study participants.

Confidentiality and anonymity

Ethical protocols ensuring participant identity is kept private (confidential) or cannot be linked to data at all (anonymous).

Deception

The practice of intentionally misleading participants about study aspects, permitted only when necessary and accompanied by debriefing.

Debriefing

A post-experimental meeting where researchers explain a study's true purpose, hypotheses, and any used deceptions to participants.

Qualitative data

Descriptive, non-numerical information captured through words, images, or observations to understand concepts, experiences, or behaviors.

Qualitative research

An exploratory research approach focused on understanding underlying reasons, opinions, and motivations through non-numerical data collection.

Qualitative vs Quantitative

The distinction between research gathering non-numerical descriptive data versus research collecting numerical metrics for statistical analysis.

Case study

An in-depth investigation of a single individual, group, or event to explore complex phenomena.

Naturalistic observation

A research method involving the systematic recording of behavior in its real-world environment without intervention or manipulation.