Ecology & populations · SL/HL
Quadrat population estimate
Scale a mean quadrat count to the habitat area.
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Number formats & units
Use decimal dots in datasets. Single values also accept decimal commas and scientific notation such as 1.2e-3 or 1.2 × 10⁻³.
Calculated locally. No account or input upload.
Result & working
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Interpretation & assumptions
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Formula & example
The relationship
What the variables mean
| Symbol | Meaning |
|---|---|
| density | Estimated individuals per unit area. |
Worked example
- Counts per quadrat
- 6 9 7 8 5 10 7 8
- Area of one quadrat
- 0.25
- Total habitat area
- 100
- Area unit
- m²
Estimated population = 3000
Follow the example steps
- mean count = 60/8 = 7.5
- density = 7.5/0.25 = 30 per m²
- estimate = density × habitat area = 30 × 100 = 3000
Common mistakes
Convert the quadrat and habitat areas to matching units.
Incorrect approach
5 per 1 m², 10000 cm²: N = 5 × 10000 = 50000
Correct approach
10000 cm² = 1 m²: N = 5 × 1 = 5
More checks before you submit
- Use matching area units for quadrat and habitat.
Method notes
Random or appropriately systematic placement matters; a numerical estimate cannot remove sampling bias.