W4 Chi Square

Contingency Table

A table that shows how the frequencies of two categorical variables are related by displaying counts for each combination of categories.

df (Degrees of Freedom)

The number of values that are free to vary when calculating a statistic; helps determine the significance of test results.

Magnitude

The size or strength of a result or effect; it shows how big or meaningful a difference or relationship is.

Levels/categories are the same but variables are different

A situation where you're comparing the same categories (like "yes" or "no") across different variables (e.g., comparing job satisfaction between two groups).

Chi-Square (χ²)

A statistical test that checks if there’s a relationship between two categorical variables by comparing expected and observed frequencies.

Goodness of Fit Test

A type of Chi-square test that checks if the distribution of one categorical variable matches an expected pattern.

Phi (φ)

An effect size used for 2x2 contingency tables; measures the strength (magnitude) of the relationship between two categorical variables.

Cramer’s V

An effect size used for larger contingency tables (more than 2x2); shows how strong the association is between two categorical variables.

d-family Statistics

A group of effect size measures (like Cohen’s d) used to show the magnitude of difference between two means.

r-family Statistics

A group of effect size measures (like correlation) used to describe the magnitude and direction of relationships between variables.

Correlation Coefficient (r)

A number between -1 and +1 that shows how strongly and in what direction two variables are related.

Effect Size

A value that shows the magnitude of a result, such as how strong a relationship is or how big a difference is between groups.