Sampling Flashcards
What is the population?
The group of people from which the sample is drawn from.
What is Oppotunity sampling?
Ppts happen to be available at the time so are recruited conveniently
What is a strength of oppotunity sampling?
Time saving and less expensive
What is a limitation of oppotunity sampling?
Not representative/ low population validity
Researcher bias as they control who to select
What is random sampling?
All members of the population have equal chances of being selected. Assigned by a random number generator or random number table.
What is a strength of random sampling?
No researcher bias
What is a limitation of random sampling?
Time consuming- list of population then have to contact those selected
Volunteer bias- can refuse to take part so sample unrepresentative
What is Systematic sampling?
Every nth number is selected from the framing sample
What is a strength of systematic sampling?
Avoids researcher bias
Usually representative
What is a limitation of systematic sampling?
Not truely unbiased unless a random number generator is used first
What is stratified sampling?
The composistion of the sample reflects the varying proportions of people in particular subgroups (strata) within the wider population. Sample randomly selected from each stratum.
What is a strength of stratified sampling?
No researcher bias- randomly within stratum
Representative data due to the proportional strata
What is a limitation of stratified sample?
Time consuming
Identified strata cannot reflect all the differences between the people of the wider population
What is volunteer sampling?
Self selection- advert/ requested
What is a strength of volunteer sampling?
Easy and not time consuming
More likely to cooperate in the study
