Geography - unit 3 - Skills - CCEA

What is population in terms of sampling

The complete set of items to be investigated

What is the key factor to consider when deriving a sample population

Sample size is large enough to gain representative

What is random sampling

Selecting a sample using a random number generator

Advantages of random sampling

• Objective and unbias

• If sample size is large, data should be representative

• Easily generated

Disadvantages of random sampling

Doesn’t take into account underlying strata or subsets

Can produce bunching

What is systematic sampling

Selection of data using pre-determined interval.

Advantages of systematic

• Easy to employ

• Appropriate for studies which require an even coverage over time or distance

Disadvantages of systematic

Higher chance of bias

Underlying pattern may be missed

Inaccessibility of some sites

What is stratified sampling