Sampling methods

Simple random sampling

Chosen at a random procedure such as drawing tickets or a random numberf generator etc.

May not be possible because we might not be able to obtain a list of everything/one in the sample

Cluster sampling

Dividing up the popuation into subgroups and then taking a few samples from each subgroup.

Only possible if what you are investigating is the same in the bigger picture e.g. if a school was split up into groups the investigation couldnt conclude something abput all students as that particular school may affect the results.

Opportunity sampling

The individuals are chosen to be apart of the investigation as the opportunity arises.

E.g. passing someone on the street

Bias = depending on what time of day could mean more retired people, students, businessmen/women

Stratified sampling

The sample set is split up into different subgroups with different characteristics such as age, gender etc.

Quota sampling

Similar to stratified sampling in the sense that the sampling set is divided inot different subgroups and then sampled but with quota sampling the subgroups have to meet a certian quota e.g. number of males and females.
This means that the person conducting the investigation has to choose the participants which can be bias.

Self-selected sample

Individuals in that sample have chosen to be in that sample. E.g. a survey

Bias = It might not get a full representation of the population if only the ones who choose to take the sample complete it

Systematic sampling

A method that uses a system to conduct a sample. E.g. out of a group of 100 every tenth person would be chosen.