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Practicles (Sampling (1) Divide the area into a grid using tape measures,…
Practicles
Sampling
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4) Use a large number of quadrats to be representative of the sea and to improve reliability of the results
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Systematic Sampling
- Stretch a tape measure across the environmental gradient (this is a transect)
- Place quadrats at regular intervals along the transect
- Record the number/ % cover of a species per quadrat
- Repeat with more transects to get data that is representative of the area
Repeats and taking mean
- Helps us to reduce human random error - Improves accuracy
- Enables us to identify and discard anomalous results
- By taking further readings we can be more certain of the range in which the true value lies
- There must be at least 3 repeats
Limitations of
Evidence
- Systematic error = Is when all readings are shifted one way- to overcome, a different method or equipment should be used
- Zero Systematic error = Is caused by the instrument not being zeroed properly so all the readings are shifted one way
- Random error = an error in measurement caused by factors which vary from one measurement to another.