SAMPS & POPS Flashcards
Population
Large number of people researcher interested in studying.
Sample
Smaller group taken from pop - not usually possible to study all members of pop
Generalisation
Sample should be representative of pop so generalisations can be made
Bias
e.g. groups under/over represented
- OPPORTUNITY SAMPLING
- uses people who are nearest / easiest to obtain
- STRATIFIED SAMPLING
Pps selected according to their frequency in a target pop.
Subgroups (or ‘strata’) are identified e.g. gender / age group. The relative percentages of the subgroups in the population are reflected in the sample.
Advantage of opportunity sampling?
Convenient, easy technique, less time consuming,
popular technique
- SYSTEMATIC SAMPLING
Pps selected using a sampling frame e.g. a set pattern - e.g. every 7th person on a list of the target pop.
- SNOWBALL SAMPLING
pps asked to assist researchers in identifying other potential subjects
- RANDOM SAMPLING
Every person in target pop has equal chance of being selected. Lottery method - all individuals in target pop numbered, placed in a tombola.
Advantage of random sampling?
Potentially unbiased - researcher has no influence over who is selected - free from researcher bias
Disadvantage of random sampling?
Representation not guaranteed - could still produce a biased sample. Limits ability to generalise.
Advantage of systematic sampling?
Unbiased - first item usually selected at random. Objective method.
Disadvantage of systematic sampling?
Time consuming, takes lots more effort. May as well use random sampling
Advantage of stratified sampling?
Characteristics of target pop are represented. More likely to be generalisable.
