sampling-research methods

Question 1

population and sample

Answer 1

population- large group that researcher is interested in studying
not possible to include all target population so smaller gorup known as sample selected
sample will be representative of target population so can be generalised
difficult to represent populations due to inevitability of diverse nature of populations of people
vast majority of samples include bias
selected using sampling technique that aims to produce representative sample

Question 2

random sample

Answer 2

all members of target popualtion have equal chance of being selected
obtain complete list of all members of target population
names on ist assigned number
selected through lottery method

Question 3

systematic sample

Answer 3

every nth member selected
sampling frame produced list of people in target population organised
sampling sytem allocated
researcher works through sampling frame until sample completed

Question 4

stratified sample

Answer 4

sampling in which the composition of the sample reflects the proportions of people in certain subgroups (strata) within the target pop or wider pop
researcher identifies different strata that make up pop
proportions neeed for sample to be representative are worked out
pps needed are worked out
pps make up each stratum selected using random sampling

Question 5

opportunity sample

Answer 5

select anyone who happens to be willing and available
takest he chance to ask whoever is around at the time of the study

Question 6

volunteer sample

Answer 6

involves pps selecting themselves to be part of the sample
self selection
may place advert
willing pps may raise their hand when researcher asks

Question 7

random sample eval

Answer 7

+ potentially unbiased, confounding or extraneous should be equally divided between different groups enhancing internal validity
- difficult and time consuming to oconduct, list of target pop difficult to obtain
- may end up with sample still unrepresentative
- may refuse to take part

Question 8

systematic sample eval

Answer 8

+ objective, researcher has no influence over who is chosen
- time consuming and may refuse to take part

Question 9

stratified sample eval

Answer 9

+ produces representative sample designed to accurately reflect composition of pop, generalisation becomes possible
- identified strat cant reflect all the ways people are different, complete represenation not possible

Question 10

opportunity sample eval

Answer 10

+ convenient, less costly because list of members is not required, no need to divide pop into differnet strata
- suffers unrepresenative drawn from specific area so findings cant be generalised, researcher has to complete control over selection of pps and may avoid people who do not like the look of- researcher bias

Question 11

volunteer sample eval

Answer 11

+ easy, requires minimal input from research and less time consuming than other forms, researcher ends up with pps who more engaged
- volunteer bias, attract certain profile of person one who is curious and more likely try to please the researcher