Chapter 1 intro to psych

Theory

Explanation using an integrated set of principles that organizes observations and predicts behaviors or events

Hypothesis

Testable prediction, often implied by a theory

Operational

Carefully worded statement of the exact procedures (operations) used in a research study

Replication

Repeating the essence of a research study, usually with different participants in different situations, to determine whether the basic finding can be reproduced

Preregistration

Publicly communicating planned study design, hypotheses, data collection, and analyses

Meta-analysis

Statistical procedure for analyzing the results of multiple studies to reach an overall conclusion

Informed consent

An ethical procedure where prospective participants are fully educated on a study's risks, benefits, and procedures before voluntarily agreeing to participate

Scatter plot

A graph displaying values of two numerical variables as points on a two-dimensional grid to show their relationship

Time-series graph

A line chart that plots data points at successive, chronologically ordered intervals of time to illustrate changes over time

Histogram

A continuous bar chart that displays the frequency distribution of a single quantitative variable grouped into adjacent, non-overlapping intervals (bins)

Pareto graph

A specialized combination bar and line chart where individual values are represented in descending order by bars, and the cumulative total is represented by a line

Frequency polygon

A line graph formed by connecting the midpoints of the tops of histogram bars to display the shape of a continuous frequency distribution

Between-subjects design

An experimental setup where each participant is exposed to only one treatment or experimental condition, comparing results across separate groups of people

Within-subjects design

An experimental setup where the same participants are exposed to all treatments or experimental conditions, comparing results across different conditions within the same group of people

Case study

An in-depth, qualitative examination of a single individual, group, or event over a period of time

Correlational research

A non-experimental research method that measures two or more variables to evaluate the strength and direction of the statistical relationship between them without manipulating variables

Experimental research

A scientific method where a researcher deliberately manipulates one or more independent variables to observe their effect on a dependent variable while controlling for extraneous variables

Positive correlation

A relationship between two variables where both variables move in the same direction, increasing or decreasing together

Negative correlation

A relationship between two variables where an increase in one variable corresponds to a decrease in the other, moving in opposite directions

Perfect correlation

A relationship where the value of one variable enables 100% exact prediction of another, represented by a correlation coefficient of exactly +1.00$ or -1.00

Significant causal relationship

A statistically validated connection demonstrating that changes in an independent variable directly produce a reliable effect on a dependent variable rather than occurring by chance

Inverse relationship

A mathematical connection between two variables where an increase in one causes a proportional decrease in the other, functionally identical to a negative correlation

How to find a perfectly predicted condition

A condition is perfectly predicted when the data fall on a straight line, meaning all observed data points lie exactly on the regression line without any prediction error (r = ± 1.00 or R² = 1.0)

Third-variable problem

A fundamental limitation in correlational research where an unmeasured extraneous variable leads to a false appearance of a causal link between two observed variables

Aggregate scores

Combined or summarized data calculated by combining multiple individual scores or data points into a single composite value (such as a total or mean)

Independent variable

The variable in an experiment that is deliberately manipulated, categorized, or controlled by the experimenter to observe its effect

Dependent variable

The variable being measured and tested in an experiment, whose values are expected to change as a result of manipulating the independent variable

Equivalent assignment

The method or outcome of dividing participants into experimental groups so that all groups are equal in key baseline characteristics prior to receiving treatment

Matched participants

A sampling technique where researchers pair participants across groups based on specific shared characteristics (like age or IQ) to balance control across conditions

Random assignment

The procedural placement of study participants into different treatment conditions using a chance procedure (such as a coin flip) so that each participant has an equal likelihood of being placed in any group

Random selection

A sampling procedure ensuring that every individual in a target population has an equal chance of being chosen to participate in a study

Confounding variable

An unobserved or unmeasured extraneous variable that correlates with both the independent and dependent variables, potentially biasing the results and casting doubt on causality

Case study

Examines one individual or group in depth, individual cases: Provide fruitful ideas, cannot be used to generalize conclusions

Naturalistic observation

Records behavior in natural environment, describes but does not explain behavior, can be revealing

Survey

Examines many cases, asking people to report their behavior or opinions

Correlation

Measure of the extent to which two factors vary together, and thus of how well either factor (variable) predicts the other

Correlation coefficient

Statistical index of the direction and strength of the relationship between two things (ranging from −1.00 to +1.00, with r = 0.00 indicating no relationship)

Positive correlation

above 0 to +1.00, indicates a direct relationship: Two things increase together or decrease together

Negative correlation

below 0 to −1.00, indicates an inverse relationship: As one thing increases, the other decreases

Variable

Anything that can vary and is practical and ethical to measure