Sampling
Biology: AQA GCSE Higher, topic 2.4.3
Sampling
Governments and health organisations track cases of diseases to inform their policy decisions. These can be global cases, or cases in a target group (called the target population). For example, the number of incidences of a particular disease in Scotland, or in 60-79 year olds in Manchester.
Big populations and sampling
- As a country's population is so large, not everybody can be tested.
- Instead, we take a sample and assume that the pattern is true for the whole population.
Sampling example
- If 10 people in a sample of 100 people have a particular disease, 10% of the sample has the disease.
- We assume that 10% of the population will also have the disease.
- If the population has 2000 people, then we predict 200 people in the population have the disease.
Test yourself on Sampling
20 people in a sample of 100 people have a particular disease. How many people can we predict to have that disease in the entire population of 5000 people?
If 35 people in a sample of 70 people have a particular disease, what percentage of the population can be assumed to also have the disease?
Why do governments take a sample of the population instead of testing every person for a disease?
How is a free sample in a supermarket similar to a sample used in disease tracking?
Which example shows a government studying a target population rather than global cases of a disease?