CurriculumGrade 9Mathematics

Two-Way Frequency Tables

Aligned to S-ID.B.5 — Common Core State Standards for Mathematics.

What this lesson teaches

A two-way table sorts data by two categories. The inside cells are joint frequencies, the row and column totals are marginal frequencies, and a conditional relative frequency divides a cell by its row or column total.

Worked example

Of 50 students, 15 of the 25 girls own a bike. The conditional relative frequency of owning a bike among girls is 15 / 25 = 0.6, or 60%.

Practice questions

  1. In a table, 30 of 80 people are the joint total for adults who walk. Interpret that cell.
  2. If a row total is 40 and a cell in it is 10, find that conditional relative frequency.
  3. Explain the difference between a joint frequency and a marginal frequency.

Watch the lesson

Every lesson comes with a video taught in English and Spanish — the same video the QR code in the printed workbook opens.

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En español

Tablas de Frecuencia de Doble Entrada

Una tabla de doble entrada clasifica datos según dos categorías. Las celdas interiores son frecuencias conjuntas, los totales de fila y columna son frecuencias marginales, y una frecuencia relativa condicional divide una celda entre el total de su fila o columna.

Ejemplo: De 50 estudiantes, 15 de las 25 niñas tienen bicicleta. La frecuencia relativa condicional de tener bicicleta entre las niñas es 15 / 25 = 0.6, o 60%.

More Statistics & Probability lessons

Displaying DataS-ID.A.1Comparing Center and SpreadS-ID.A.2Outliers and Their EffectS-ID.A.3Slope and Intercept in DataS-ID.C.7The Correlation CoefficientS-ID.C.8Correlation vs. CausationS-ID.C.9

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