19.4 - Random Sampling Flashcards
What random sampling is How to prevent sampling bias and reduce the effects of chance Random sampling techniques for plants and animals
1
Q
Why is random sampling important?
A
Avoid bias
2
Q
How does random sampling work?
A
- Choose an area.
- Randomly generate coordinates across the area - This prevents sampling bias by removing human involvement in choosing samples.
- Collect samples from random coordinates - This gives us samples that are representative of the population.
- Repeat this several times - This gives us a large sample size and minimises the effects of chance.
- Analyse the data collected - This lets us identify any relationships.
3
Q
What is a quadrat?
A
Frame used to sample organisms in an area
4
Q
What are the two types of quadrats?
A
Point quadrat
5
Q
What is a point quadrat?
A
Frame with horizontal bar
6
Q
What is a frame quadrat?
A
Square frame divided into a grid
7
Q
How is species frequency calculated?
A
(Number of quadrats species is found in / Total number of quadrats) x 100
8
Q
What is percentage cover?
A
Estimate of area a species covers within a quadrat
