U0 Psych In-Class Notes

Correlation

Expresses a relationship between two variables.

Illusory Correlation

The perception of a relationship where none exists.

Correlation Coefficient

A number that measures the strength of a relationship, ranging from -1 to +1.

Positive Correlation

The variables go in the same direction.

Negative Correlation

The variables go in opposite directions.

Correlation does NOT equal causation

The principle that correlation between two variables does not imply that one causes the other.

Experiment

A study designed to test causal relationships by manipulating variables in a controlled environment.

Survey Method

A common type of study in psychology that measures correlation through questionnaires or interviews.

Random Sample

A sample that fairly represents a population because each member has an equal chance of inclusion.

Independent Variable (IV)

The variable that is manipulated in an experiment.

Dependent Variable (DV)

The variable that is measured in an experiment to see if it is affected by the independent variable.

Operational Definition

A statement that explains what is meant by the variable in a hypothesis.

Population

All the cases in a group from which samples may be drawn for a study.

Sample

A subset of the population that is used to represent the group being studied.

Random Assignment

Assigning participants to experimental and control groups by chance, to minimize pre-existing differences.

Experimental Group

The group of participants that is exposed to the treatment in an experiment.

Control Group

The group that does not receive the experimental treatment and is used for comparison.

Confounding Variables

Any variables that could cause changes in the dependent variable alongside the independent variable.

Double-Blind Procedure

An experimental procedure in which both the researchers and participants are unaware of who receives the treatment.

Hawthorne Effect

Changes in participant behavior that occur when they know they are being observed.

Placebo Effect

A beneficial effect produced by a placebo treatment that arises from the patient's expectations.

Order Effect

A change in participants' performance resulting from the order in which treatments are presented.

APA Ethical Guidelines for Research

Standards that govern how researchers must conduct studies involving human and animal subjects.

Informed Consent

Participants must be fully informed about the nature and risks of the study before agreeing to take part.

Anonymity

The ethical principle requiring researchers to protect participants' identities.

Statistical Significance

A statistical statement regarding how likely it is that a result occurred by chance.

Descriptive Statistics

Statistics that summarize or describe characteristics of a data set.

Central Tendency

Measures that represent the center of a data set, including mean, median, and mode.

Standard Deviation (SD)

A measure of how much scores vary around the mean in a data set.

Z Score

A statistic that indicates how many standard deviations a data point is from the mean.

Inferential Statistics

Statistical methods that allow conclusions to be drawn about a population based on sample data.

P-value

The probability of obtaining results at least as extreme as the observed results, given that the null hypothesis is true.

Mean

The average value of a set of numbers.

Median

The middle value in a list of numbers arranged in order.

Mode

The most frequently occurring value in a data set.

Range

The difference between the highest and lowest values in a data set.

Normal Distribution

A bell-shaped distribution where most of the data points cluster around the mean.

Outliers

Data points that are significantly different from the rest of the data set.

Positive Skew

A distribution that has a long tail on the right side due to high outlier scores.

Negative Skew

A distribution that has a long tail on the left side due to low outlier scores.

Statistical Analysis

The process of collecting and examining data to discover patterns or trends.

Random Assignment

Method used to assign participants to different groups in an experiment, aiming to eliminate pre-existing differences.

Field Experiment

An experiment conducted in a real-world setting rather than in a laboratory.

Laboratory Experiment

An experiment conducted in a controlled environment where variables can be manipulated.