Research Design in Psychology

Unit 0.4

Positive correlation

Two variables move in the same direction

Negative correlation

Two variables move in the opposite direction

Strong correlation

Data points are close together

Weak correlation

Data points are farther away from each other

Correlation Co-efficient

A correlation co-efficient falls between 1 and -1. Typically referred to as “r”. If the number is closer to 1, it is positive. If the number is closer to -1, it is negative. Shows how strong the linear relationship is.

Linear relationship

A connection between two variables that forms a straight line when plotted on a graph

Illusory Correlation

A cognitive bias in which a person perceives a relationship between two separate things, events, or variables when that is untrue

Regression Towards the Mean

A statistical rule that extreme or unusual behavior/scores will be followed by more average results

Independent variable

Researchers intentionally change this variable

Dependent variable

Researchers observe this variable

Controlled variable

Researchers keep this variable the exact same for both groups

Control groups

Studies compare a group that gets special treatment (experimental) against a group that does not (control)

Random Assignment

Pariticpants placed into different groups by chance, which prevents bias from skewing the outcome

Likert Scales

A survey presents a declarative sentence where a user picks an answer from a range of numbers

Methods to isolate cause and effect in experiments

Variable manipulation, control groups, random assignment

Directionality Problem

When two variables are statistically related, but it is impossible to determine if variable X causes variable Y or the other way around

Third Variable Problem

When an unmeasured or uncontrolled factor causes a false connection between two other variables that only appear to be linked

Quantitative Research

Collecting and analyzing numerical data

Qualitative Research

Collecting and analyzing non-numerical data

Single-blind Procedure

An experimental design where participants don’t know if they’re receiving the actual treatment or a placebo

Double-blind Procedure

When both the researcher and participant don’t know if they’re receiving the actual treatment or a placebo

Placebo Effect

Symptoms improve after receiving a fake treatment, driven by the idea it was real

Confounding Variable

A third factor that affects the in/dependent variable, creating a false relationship between them

Experimenter Bias

When a researchers’ own expectations or desires skew the results, data or participant behavior

Self-report Bias

When people provide inaccurate/misleading information about themselves in surveys

Social Desirability Bias

The tendency of people to present themselves in ways that align with social norms to please others

Validity

Does the test accurately measure what it claims to measure?