Unit 0: Ap Psychology Vocab

Statistics

Bimodal distribution

A set of data that has two distinct peaks (modes), indicating that two different values appear with the highest frequency within that dataset.

Central Tendency

Statistical indicators that pinpoint the center or average of a dataset, representing the typical or representative value of a group.

Correlation

The statistical relationship between two variables. If one variable changes, there tends to be a consistent change in the other variable.

Correlation Research

Investigates the relationship between two or more variables, where the correlation coefficient indicates the strength and direction of this relationship.

Correlation Coefficient

Numerical value that represents the strength and direction of a correlation. A value close to +1 that indicates positive while -1 correlates to negative.

Convenience Sampling

Selecting participants for a study based on their immediate availability and easy access, rather than through random selection.

Directionality problem

A relationship is found between two variables (X and Y) but it is unclear if X causes Y, Y causes X, or if another third variable is responsible for the relationship

Effect Size

A statistical measure of the magnitude or strength of the relationship between two variables or the size of the difference between groups in a study.

Mean

The mathematical average of a dataset, calculated by summing all values and dividing by the number of values.

Median

A measure of central tendency that represents the middle score in a dataset when all the values are arranged in ascending or descending order.

Meta-analysis

A statistical technique that combines and analyzes the quantitative data from multiple independent studies to reach a more robust conclusion about a common research question or the effectiveness of an intervention.

Mode

The most frequently occurring score(s) in a distribution.

Negative Correlation

The most frequently occurring score(s) in a distribution. a relationship between two variables where, as one variable increases, the other variable decreases

Positive Correlation

A relationship between two variables where both variables tend to increase or decrease together, meaning they move in the same direction.

Sampling Bias

Occurs when a flawed sampling process results in a sample that does not accurately represent the entire population, leading to inaccurate or misleading research findings

Scatterplot

Visually represents the relationship between 2 variables

Negative Skew

A dataset where the majority of the scores are clustered on the high end of the distribution

Percentile Rank

The percentage of scores that are lower than a given score.

Skew

A statistical pattern where data points are not evenly distributed but cluster more on one end of a scale.

Positive Skew

Describes a dataset where the scores bunch up on the left (low end) of the distribution, and a few extremely high scores create a long "tail" or spread out to the right (high end)

Normal Curve

A symmetrical, bell-shaped frequency polygon where most scores cluster around the mean

Population

The entire group of individuals that a researcher wishes to study and understand, from which a representative sample is drawn to conduct the research

Random sample

A subset of a population where every member of that population has an equal chance of being selected for a study.

Range

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

Regression towards the mean

The statistical tendency for extreme or unusual scores to move closer to the average when measurements are taken again.

Representative Sample

A sample of individuals selected from a larger population in a way that accurately reflects the various characteristics of that population as a whole

Sample

A subset of a population

Variation

Refers to the differences within a population or dataset, measured by statistical terms like range or standard deviations

Standard Deviation

Measures how much individual scores in a data set are spread out or dispersed from the average score (the mean)

Statistical Significance

The likelihood that a research finding resulted from chance rather than an actual effect, determined by comparing the observed data to the null hypothesis.

Third Variable Problem

Where a relationship between two variables may be misleading because of a unmeasured variable is actually causing it