A researcher investigated variation in body mass in 60 adults from the same age range.
The adults were randomly allocated to two groups of 30. Both groups followed the same activity programme for 12 months. Adults following diet B received a greater mass of food each day than adults following diet A.
The table shows their body masses after 12 months.
| Body mass in kg | Number following diet A | Number following diet B |
|---|---|---|
| 50.0–59.9 | 3 | 0 |
| 60.0–69.9 | 8 | 3 |
| 70.0–79.9 | 13 | 8 |
| 80.0–89.9 | 5 | 13 |
| 90.0–99.9 | 1 | 6 |
Explain what the results suggest about the causes of variation in body mass. Predict the shape of the distribution if body mass were measured in a much larger random sample of adults.
96 exam-style questions on Edexcel GCSE Biology 3.4 Variation and the Human Genome Project, covering 3.4.1 Causes of variation, 3.4.2 Outcomes of the Human Genome Project, 3.4.3 Genetic variation within a population, and 3.4.4 Effects of genetic mutations on phenotype. Each one has a worked solution and a mark scheme showing where the marks go.