Sample — Science definition
The part of an area actually counted, from which the whole is estimated; everything depends on whether it represents the whole.
Where it is taught
- Sampling Ecosystems & Comparing Evidence — Ecological Evidence & Environmental Design, Life Science & Scientific Inquiry, Grade 7
In use
A sample is the part counted, and everything downstream depends on whether it represents the whole.
Sampling Ecosystems & Comparing Evidence
Questions using sample
Problem 1
Does sample density establish the exact habitat total?
Answer and explanation
No. Extrapolation depends on sample representativeness, area definitions, and detection.
Problem 2
Illustrative four 1 m² plots contain 2, 4, 3, and 3 plants of one species. A habitat area is 20 m².
Find sample density, calculate an extrapolated count, and state the assumptions that prevent calling it a complete census.
Answer and explanation
The sample density is 3 plants/m² and the extrapolated count is 60 plants. It is an estimate assuming the plots represent the 20 m² habitat and detection is adequate. Patchiness, omitted zones, or missed plants could change the result. The supplied data do not establish an exact total.
Total count: 12 across 4 m².
Density: 12/4=3 plants/m².
Estimated larger count: 3×20=60.
Response criteria
- Explain the relevant biological process accurately.
- Use the supplied evidence and show calculation steps with units where needed.
- Connect a labeled model or mechanism with the claim.
- State an assumption, evidence limitation, or useful next observation.