Contingency Tables (AQA A-Level Further Maths): Flashcards

Relationship between two categorical variables

$\frac{\text{row total} \times \text{col total}}{\text{grand total}}$

At least 5

$X^2 = \sum \frac{(O_i - E_i)^2}{E_i}$

$(m-1) \times (n-1)$

2×2 contingency tables only

No association between the variables

Group similar categories together

Positive or zero (differences are squared)

$X^2 \geq$ crit. value or p-value $<$ significance level