8th Grade · Statistics & Probability
Joint Frequency
8.SP.A.4
Definition
The count in a single inner cell of a two-way table, representing how many data values fall into one specific combination of both categories.
Teach it
Where it is taught, with guided notes, practice, homework, an exit ticket and an interactive Teacher Deck.
Examples
- 20 people like both dogs AND cats — that's the joint frequency.
- Joint = an inner cell; marginal = a total on the edge.
Key rule
A joint frequency is a count inside the table, not a total.
Memory hook
One exact combination, counted.