sampling techniques

Question 1

What is random sampling?

Answer 1

-sample sites are randomly selected, -for example by using random number, generators to make coordinates or using a portable global positioning, satellite system in habitats

Question 2

What is opportunistic sampling?

Answer 2

research are useless prior knowledge to make sampling decisions
e.g. Deliberately sampling specific areas.

Question 3

What is stratified sampling?

Answer 3

dividing a habitat in two areas which appear different and sample each area separately

Question 4

What is systematic sampling?

Answer 4

samples taken at fixed intervals across habitats
e.g. Using line/belt transects

Question 5

Advantages of random sampling

Answer 5

No bias

Question 6

Disadvantages of random sampling

Answer 6

-May not cover all areas equally
-Species with low presence may be missed

Question 7

Advantages of opportunistic sampling

Answer 7

Easier and quicker than random

Question 8

Disadvantages of opportunistic sampling

Answer 8

The data may be biased e.g. Colour may entice researcher which would lead to an overestimate.

Question 9

Advantages of stratified sampling

Answer 9

ensures all the different areas of a habitat, a sample and species are not underrepresented

Question 10

Disadvantages of stratified sampling

Answer 10

possibility that this may lead to over representation of some areas in this sample

Question 11

Advantages of systematic sampling

Answer 11

particularly useful when the habitat shows a clear gradient in some environmental factors
e.g. Getting drier further from the pond.

Question 12

Disadvantages of systematic sampling

Answer 12

only the species on the line or within the belt are recorded and other species may be missed which would lead to an underestimate