Sampling Flashcards
What are the types of sampling?
Random sample, Systematic sample, Stratified sample, Opportunity sample, Volunteer sample
What is a random sample?
All members of the TP have an equal opportunity of getting selected.
How to do a random sample?
Take your target group, give each one a unique number, using a random number generator pick out however many numbers you need, contact them.
What is a systematic sample?
When every nth member of the TP is selected.
How to do systematic sampling?
A sampling frame is produced (A list of everyone in the TP organised e.g alphabetical order), a sampling system is nominated, work through the sampling frame until the sample is complete.
What is stratified sampling?
The composition of the sample represents the proportions of people in certain strata (sub-groups) within the TP.
How to do stratified sampling?
Identify strata, work out proportions, use random sampling to make up each stratum.
What is opportunity sampling?
Allow anyone willing and available to come and join the experiment.
What is volunteer sampling?
Participants volunteer themselves to be part of the sample.
Evaluation of Random sampling
Free from researcher bias, Difficult and time consuming, Refusing to participate.
Evaluation of systematic sampling
Avoids researcher bias, Fairly representative.
Evaluation of stratified sampling
Avoids researcher bias, Representative, Strata cannot show all the ways people are different.
Evaluation of opportunity sampling
Convenient, Drawn from a specific area, Researcher has complete control over the participants.
Evaluation of volunteer sampling
Easy, Volunteer bias (attracts a certain type of person).
Define volunteer bias
When asking for volunteers it will only attract a certain types of person
