Population and Sampling Flashcards
Definition of a population
A group of people who are the focus of the researcher’s interest, a smaller sample is drawn from this
What is random sampling?
When every member of the target population has an equal chance of being chosen
What are 2 advantages of random sampling?
- There is no researcher bias
- Confounding variables should be distributed evenly
What are 3 disadvantages of random sampling?
- Time consuming
- Participants may refuse to take part
- May randomly draw a non representative sample
What is systematic sampling?
Every nth member of the target population is selected
What are the 2 steps to complete systematic sampling?
- Create a list of the target population in an order
- Take a sample from this list
What is the advantage of systematic sampling?
- Researcher has no influence once the system is chosen, avoids bias
What is a disadvantage of systematic sampling?
- Could still draw a non representative sample
What is opportunity sampling?
Sample carried from people who are available and willing when the study is carried out
What are the advantages of opportunity sampling?
- Less costly
- Convenient
What is the disadvantage of opportunity sampling?
- Unrepresentative of the target population
What is stratified sampling?
The sample reflects proportions of certain subgroups in the target population
What is an advantage of stratified sampling?
Avoids researcher bias
What is the disadvantage of stratified sampling?
Complete representation of the population is not possible
What is the definition of experimental design?
How you allocate your participants to different conditions
