GCSE Geography Human fieldwork paper 3 write up - Gloucester dock

What's random sampling?

One that has no bias and in which anything has an equal an equal chance of being selected.

What's opportunistic sampling?

Gaining data as and when you can / as necessary

What's systematic sampling?

Samples are taken at regular/fixed intervals, for example every 3rd person that walks by.

What's stratified sampling?

Based on knowing something in advance, either about the population of the city or about the river. i.e. if yo know the ages of a village, you must have a representative sample of each age group.

What's bias in sampling?

Its possible through poor choice of sampling method or insufficient evidence, to achieve a result that's unrepresentative. Eg. Taking samples on a different day/week on a river will distort the results.

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