Data Analysis Concepts

Relative frequency is the fraction or percentage of times a value occurs out of the total number of observations. It converts raw counts into proportions, enabling fair comparisons between groups of different sizes.

"Instead of saying '15 students picked pizza,' you say '15 out of 50' or '30%.' Relative frequency compares to the whole, making different-sized groups comparable."

Why it matters: Relative Frequency gives students a careful language for comparing variables without jumping to a causal story. It is useful for reading scatter plots, two-way tables, regression models, and real-world claims where patterns are tempting but hidden variables may matter.

Conditional relative frequency is the proportion of cases in one group that also belong to another category, measured within a chosen row or column total of a two-way table. Joint and marginal relative frequencies describe the cell shares and row or column totals that support this calculation.

"A two-way table becomes much more informative once you stop reading raw counts and start reading percentages within the relevant group."

Why it matters: Conditional Relative Frequency gives students a careful language for comparing variables without jumping to a causal story. It is useful for reading scatter plots, two-way tables, regression models, and real-world claims where patterns are tempting but hidden variables may matter.