Sampling

What is opportunity sampling?

Participants happen to be available at the time of the study, so pps are recruited conveniently

What is a strength of opportunity sampling?

Easy method of recruitment, time saving, inexpensive

What are some limitations of opportunity sampling?

Isn't representative of whole population which makes it lack generalisability.

Researcher bias as they control who is selected

What is random sampling?

When all members of a target population have an equal chance of getting selected

How can random sampling be carried out?

Each member of a population is assigned a number and a random number generator is used to randomly choose a ppt

What is a strength of random sampling?

No researcher bias as they don't have an influence in who's picked

What are some limitations of random sampling?

Is time consuming as every member of a population is listed and need to be contacted

Volunteer bias as ppts can choose not to participate ending up with an unrepresentative sample

What is systematic sampling?

Where every nth member of the target population is selected

What is a strength of systematic sampling?

Avoids researcher unbiased and is fairly representative of a population

What is a limitation of systematic sampling?

it takes more time and effort than other methods

What is stratified sampling?

Dividing the population into subgroups (strata) then selecting a sample from each of these groups

How can you carry out stratified sampling?

You can try to identify a strata and then calculate the required proportion needed for each stratum based on the target population. Then select a sample at random from each stratum using a random selection method.

What is a strength of stratified sampling?

No researcher bias as the selection within the stratum is done randomly

Produces representative data due to the proportional strata making generalisation possible

What are some limitations of stratified sampling?

Is time consuming to identify strata and contact people from each strata.

What is volunteer sampling?

Where the participant pick themselves through seeing advert or when asked to

What is a strength of volunteer sampling?

Quick access to willing participants, making it easy to do and not time consuming.

As participants are willing to do study, they are more likely to cooperate.

What are some limitations of volunteer sampling?

Volunteer bias may occur due to the study attracting a particular type of person affecting generalisability

Motivations like money could drive participation, so ppts may not take study seriously