The chi-squared test

Edexcel International A Level Biology (YBI11), chapter 15: Ecology, specification point A.1.9. Part of the full course.

Read the revision notes · International A Level Biology past papers

The chi-squared test compares observed counts with the counts expected if the null hypothesis is true. It helps you decide whether a difference between the counts is likely to be real or could be due to chance.

More lessons in Ecology

Population, community, habitat and ecosystem
Succession: from colonisation to climax
Abiotic factors and population size
Biotic factors: predation, competition and disease
How the niche explains distribution and abundance
Core practical 11: random sampling with quadrats
Core practical 11: transects and abiotic measurements
Null hypotheses and choosing a statistical test
Spearman's rank correlation coefficient
Student's t-test