A-Level Edexcel Biology A2 Statistical Tests

A-Level Edexcel Biology A2 Statistical Tests
Pearson Edexcel International Advanced Subsidiary/Advanced Level in Biology, Issue 2, February 2021Biology XBI11/YBI11

Review A-Level Edexcel Biology statistical tests through the available evidence on using correlation coefficients to judge relationship strength.

How this is tested

  • describe how a correlation coefficient tests relationship strength against critical values

Question 5(c)(ii)

[Maximum number: 3]

Mycobacterium tuberculosis (Mtb) and human immunodeficiency virus (HIV) are two pathogens that infect people. When people infected with either pathogen become infected with the other pathogen the disease is worse.

The graph shows the number of people who have TB and the percentage of the population who have HIV. Each plotted point represents data from a different country. Number of people who have TB per 100000 population

Figure for Question 5(c)(ii) — Edexcel A-Level Biology A2

Describe how the strength of the relationship between the number of people who have TB and the percentage of people who have HIV could be determined.