Chi-squared Test (AQA A-Level Biology): Flashcards

Statistical method to test if observed and expected results differ significantly

$\chi^2 = \Sigma\frac{(O - E)^2}{E}$

Observed numbers

Expected numbers

Number of classes (categories) minus one

$p = 0.05$ (5% probability threshold)

When probability $> 0.05$ (deviation not significant)

When probability $< 0.05$ (deviation is significant)

Over 20

9:3:3:1