Set 4: Statistical Analysis

Mean

The average of a distribution.

Sum of all values ÷ Total number of values

Median

The middle score in a distribution.

Mode

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

Range

The difference between the highest and lowest scores in a distribution.

Standard Deviation

How spread out values are from the mean.

Normal Curve

Bell-shaped curve where most values cluster at the mean.

Positive Skew

Tail extends to the right (high outliers).

Negative Skew

Tail extends to the left (low outliers).

Bimodal Distribution

Two distinct peaks or frequent values.

Percentile Rank

Percentage of scores falling at or below a specific score.

Statistical Significance (p-value)

Likelihood results occurred by chance.

Effect Size

Measures the strength or magnitude of a finding.

Correlation Coefficient

Measures strength and direction of a relationship (–1 to +1).

Positive Correlation

Occurs when both variables increase together or decrease together; as one variable increases, so does the other.

Negative Correlation

Occurs when one variable increases as the other decreases, and vice versa.

Strength (Correlation)

How close the coefficient is to –1 or +1.

Positive/Negative Relationship

Describes direction of change between two variables.

Scatter Plot

A graph that visually represents the relationship between two variables.

Illusionary Correlation

The perception of a relationship where none exists. An example of this would be stereotypes.

Histogram

A bar graph depicting a frequency distribution.