SAMPLING METHODS

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What are the three types of sampling?

1. Random

2. Systematic

3. Stratified

Random sampling

Every individual or group has an equal chance of being selected

How are organisms randomly picked in random sampling?

Through a lottery or computer-generated numbers

Is random sampling biased or unbiased? Why?

It is unbiased, because it is representative of the entire area

Systematic sampling

Selects from a larger population in a structured way

Is systematic sampling biased or unbiased? Why?

It is unbiased, because it has a larger sample to work with

Stratified sampling

Height and depth is taken into account, involving different levels called strata, ensuring each level is fully represented

What are 2 ways to minimise bias?

1. Manipulating sample size

2. Randomness

What happens when only one line of a meadow is sampled? Is it biased or not?

It is biased, because other species would be excluded, thus the whole area would be unrepresented

Does a larger or smaller area increase accuracy in sampling?

A larger area increases accuracy

Would repeated samples increase accuracy in sampling?

Yes, repeating samples would increase accuracy

How would sampling randomly minimise bias?

Both visible and camoflauged species would be sampled for accuracy

What are the 2 steps to random sampling?

1. Divide areas into squares

2. Use a random generator for random selection

What are the 3 steps to systematic sampling?

1. Arrange population/area in a clear order

2. Choose a random starting point within list

3. Select samples at regular intervals from the start

What is the key trait of stratified sampling?

It involves levels