Psychological Science, Research Methods & Data Interpretation

Peer Reviewers

A process in which experts in that field ensures the validity of the results of a research process.

Hypothesis

Usually produced from a theory, a hypothesis is a testable prediction (if-then) formulated to prove/disprove a theory

Falsifiable

A scientific theory or hypothesis that can in principle be proven through observation or experimentation

Operational Defintion

Definitions that eliminate bias, for example sleep deprived may be defined as “X hours less“

Replication

Producing the same results with different participants

Case Study

A descriptive technique in which one individual or group is studied in depth in order to reveal universal principles

Naturalistic Observation

Recording the natural behavior of many individuals without manipulation

Sample

A smaller manageable group of individuals selected from ma larger population to participate in a research study

Population

All the people/ things in a group being studied from which samples may be drawn

Random Sample

A sample that fairly represents a population because each member/group of a population has a equal chance of inclusion

Convenience Sampling

A non-random sampling method in which researchers use the most accessible participants

Representative Sample

A sample that can represent all groups and situations

Generalizing

The ability to apple learned knowledge, behaviors, or responses, to new and similar situations

Structured Interview

A formalized method for gathering information, where the interviewer asks questions in a fixed order with meticulous wording and a standardized format.

Social Desirability Bias

The tendency to answer questions/ act a certain way to show yourself in a favorable light

Correlation

A measure of the extent to which two factors relate to each other, and thus how well the factors can predict each other

Correlation Coefficient

A statistical index of the relationship between two factors (Between +1.00 to -1.00)

Independent Varibale

The element in an experiment that is being manipulated in order to effect another variable

Dependent Variable

The element(s) in an experiment that is expected to change based on a manipulation of the ind. variable

Confounding Variable

An external variable in a study that affects both ind. and dep. variables which the runner of the experiment is unaware of

Scatterplot

Type of graph where dots are plotted according to an x and y axis and can be traced for a certain slope

Positive correlation

A correlation where both sets (x and y) are going up (close to +1.00)

Negative Correlation

A correlation where one set is going up and another is going down (closer to -1.00)

Regression Towards the Mean

The tendency for extreme of abnormal scores or events to fall back towards the average (mean)

Experiment

A research method in which an investigator manipulates one or more variables to observe the effect on another

Experimental Group

In an experiment, the group exposed to the treatment

Control Group

In an experiment the group not exposed to the treatment

Random Assignment

Randomly assigning participants to experimental and control groups, equalizing the groups

Single-Blind

When the participants is unaware of which type of treatment they have been administered (placebo/real)

Double-Blind

When the participants and researchers are unaware of which type of treatment they have been administered (placebo/real)

Placebo

A fake, that is meant to show the actual effect of the active treatment

Placebo Effect

Experimental results caused by expectations alone

Experimenter Bias

When a researcher's beliefs influence the outcome of the study

Bimodal Distribution

Data that has two distinct peaks, or modes, representing two different patterns in one dataset

Representation of Participants

A representative sample that mirror a population, allowing for valid generalization

Likert Scales

A scale commonly used in surveys to measure attitudes, opinions, or behaviors by asking respondents to indicate their level of disagreement

Replication

A way of verifying the reliability and validity of an experiments original results

Directionality Problem (In Correlation)

The difficulty in determining which two correlated variables causes the other

Third Variable Problem (In Correlation)

When a statistical relationship between two variables is caused by an unmeasured variable

Quantitative Research Method

The objective collection and analysis of numerical data to test hypotheses

Qualitative Research Method

Exploration of non-numerical data to understand complex behavior

Informed Consent

Written consent given after particpant is given enough information enable them to choose whether they wish to participate.

Debriefing

The process of telling participants after the experiment what they wished to achieve and any deception

Informed Assent

Giving participants (who may not be able to consent) enough information about a study to make an informed decision to participate or not participate

IRB

Boards that review the ethics of a study and point out ethical concerns

Protection from Harm

A fundamental ethical principle in psychology that ensures the well being of participants

Confidentiality

Fundamental ethical principle that protects the privacy and sensitivity of the client's info

Deception

Any trick on the participant used to mislead them into believing something.

Mean

Average

Median

Middle of scores (123, Median = 2)

Mode

Most frequently occurring score

Percentile Rank

The percentage of scores in a comparison group that fall at or below a particular score

Skewed Distribution Positive

Mean > Median > Mode

Skewed Distribution Negative

Mean < Median < Mode

Range

Difference between the highest and lowest scores in distribution

Standard Deivation

A statistical measure that quantifies the amount of variation or dispersion in a set of scores, showing how much individual data points tend to differ from the average (mean) score

Normal Curve

Symmetrical bell shaped curve

Meta-Analysis

A statistical method for combining and analyzing the results from multiple independent but similar studies to determine an overall effect or conclusion

Statistical Significance

A statistical statement of how likely it is that an obtained result occurred by chance

Central Tendency

A single value that summarizes the typical or central point of a dataset

Variation

A difference or change from a standard or usual form

Effect Sizes

A statistical measure that quantifies the magnitude of an observed effect