Unit 0

Experiment

A research method in which an investigator manipulates one variable (independent variable) to observe its effect on another variable (dependent variable), while controlling for other factors, to establish cause-and-effect relationships.

Correlation

A statistical relationship between two variables, where changes in one variable are related to changes in another, but without implying causality. It can be positive (both variables move in the same direction) or negative (variables move in opposite directions).

Correlation Coefficient

A numerical value, usually between -1 and +1, that quantifies the strength and direction of the relationship between two variables. A positive value indicates a direct relationship, while a negative value indicates an inverse relationship. A value closer to 1 or -1 suggests a strong correlation, while closer to 0 suggests a weak or no correlation.

Generalizability

The extent to which the findings of a study can be applied or extended to settings, populations, or times beyond the specific conditions or sample used in the study.

Independent Variable (IV)

The variable in an experiment that is manipulated or changed by the researcher to observe its effects on the dependent variable. It's the presumed cause in a cause-and-effect relationship.

Scatterplot

A graphical representation of data points on a two-dimensional plane, where each point represents values for two variables. It helps visualize the relationship or correlation between the variables.

Case Study

An in-depth, detailed examination of a single individual, group, or event. Case studies are often used to explore rare or complex phenomena.

Dependent Variable (DV)

The variable in an experiment that is measured or observed to assess the effect of changes in the independent variable. It's the presumed effect in a cause-and-effect relationship.

Naturalistic Observation

A research method where the researcher observes and records behavior in its natural setting, without interfering or manipulating the environment. It is useful for studying behaviors in real-world contexts.

Meta-Analysis

A statistical technique that combines the results of multiple studies on a specific topic to provide a more comprehensive and reliable conclusion about the overall effect or relationship.

Standard Deviation

A measure of the amount of variation or dispersion in a set of data. A low standard deviation indicates that data points are close to the mean, while a high standard deviation indicates a wider spread of data points.

Operational Definition

A specific, measurable definition of a variable that outlines how it will be measured or manipulated in a study, ensuring that it is clear and replicable.

Mean

The arithmetic average of a set of numbers, calculated by summing all the values and dividing by the number of values.

Median

The middle value in a sorted set of numbers. If there is an even number of values, the median is the average of the two middle values.

Mode

The value that appears most frequently in a set of data. A set of data may have one mode, more than one mode, or no mode at all if no number repeats.

Likert Scales

A survey instrument that uses a scale (typically 1-5 or 1-7) to measure attitudes or opinions. For example, a Likert scale may ask respondents to rate their agreement with a statement from 'Strongly Disagree' to 'Strongly Agree'.

Correlational Research Method

A research method used to examine the relationships between two or more variables without manipulating them, determining how the variables are related.

Confounding Variable

An extraneous variable that is not accounted for in a study, which may affect the dependent variable. For example, if studying the effect of exercise on weight loss, diet could be a confounding variable if not controlled.

Random Assignment

The process of randomly assigning subjects to different groups in an experiment to ensure each participant has an equal chance of being assigned to any group, which helps eliminate biases.

Placebo Effect

The phenomenon where participants experience a perceived improvement in condition or behavior due to their expectations, rather than because of any actual treatment.

Single-Blind Study

A study in which the participants do not know whether they are receiving the treatment or a placebo, reducing bias due to participants' expectations.

Double-Blind Study

A study design where neither the participants nor the experimenters know who is receiving the treatment or a placebo, minimizing biases from both sides.

Random Sample

A sample that is selected from a population in such a way that every individual has an equal chance of being chosen, increasing the representativeness of the sample.

Range

The difference between the maximum and minimum values in a dataset, indicating the span of the data.

Positive Skew

A distribution where most values are clustered at the lower end, resulting in a tail on the right side. For example, income distribution often displays a positive skew.

Negative Skew

A distribution where most values are clustered at the higher end, resulting in a tail on the left side. An example would be the distribution of exam scores if most students score high.

Statistical Significance

A determination that results observed in a study are unlikely to be due to chance, often established when a p-value is less than a predetermined level (commonly 0.05).

Effect Size

A quantitative measure of the magnitude of a phenomenon, often used to assess the strength of an observed effect in research.

Informed Consent

A process in which a participant is fully informed about the study's purpose, procedures, risks, and benefits before agreeing to participate. This ensures that participation is voluntary and based on sufficient understanding.

Informed Assent

A process for obtaining permission from minors and those unable to give full consent and their legal guardians to participate in research.

Confidentiality

The ethical principle that ensures personal data collected from research participants is kept private and not disclosed without consent. Researchers must take measures to protect participants' identities.

Deception

The practice of withholding information or misleading participants about certain aspects of a study. It can be used in research to prevent bias, but must be justified and addressed during debriefing.

Confederates

People who are part of a research study but are not the actual subjects; they act as if they are participants to manipulate the social environment in the study.

Debriefing

The process of informing participants about the study's purpose, procedures, and any deception used, following their participation. It's crucial for ethical considerations and helps address any questions or concerns from participants.