Sampling

Question 1

What is random sampling?

Answer 1

All community have an equal chance of being selected (using quadrat).

Question 2

What is systematic sampling?

Answer 2

Data gathered according to system, usually fixed intervals from a fixed point. (using transect).

Question 3

Model answer for random sampling:

Answer 3

-Create grid using 2 tape measures.
-Create random co-ordinates using random number generator.
-Take samples where two co-ordinates intersect (using quadrat).
-Repeat to calculate a mean.

Question 4

What is the positives of using random sampling?

Answer 4

-Removes researcher bias.

Question 5

What are some negatives of using random sampling?

Answer 5

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

Question 6

What is the positives of using systematic sampling?

Answer 6

-Useful when environment shows clear gradient in environmental factors.

Question 7

What is the negatives of using systematic sampling?

Answer 7

-Only species on line are recorded so can lead to an underestimate.
-bias as can choose where line goes.

Question 8

What are some non-sampling errors?

Answer 8

-Over/under coverage.
-Measurement errors.
-Processing errors.
-No response.