# Explain why scientists use random sampling when investigating the biodiversity of a habitat.

> AQA A-Level Biology (7402) — 3.4.7 Investigating Diversity · Explain · 5 marks

> A group of students wants to estimate the number of different species of plants in a meadow. They decide to use quadrats to collect data.

## Mark scheme (5 marks)

1. Random sampling avoids bias (in the placement of quadrats)
2. So that results are representative of the whole habitat / population
3. A larger sample size reduces the effect of chance / anomalous results
4. Results can be used to estimate species diversity / number of species across the whole habitat
5. Random sampling can be achieved by using a random number generator / coordinates to place quadrats

## Key terms

- [random sampling](https://www.gradenine.co.uk/glossary/random-sampling)
- [biodiversity](https://www.gradenine.co.uk/glossary/biodiversity)

## Related

- [Revision notes for AQA A-Level Biology (7402)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/explain-why-scientists-use-random-sampling-46b8bd88) · Published by Druglandscape Ltd.