populations and sampling Flashcards
define a population
a group of people who are the focus of the researchers interest (from which a smaller sample is drawn)
define sample
a group of people who take part in a research investigation
define sampling techniques
methods used to select people from the population
define bias
when certain groups are under/over represented within the sample selected
what are the 5 types of sampling
random
systematic
stratified
opportunity
volunteer
explain what random sampling is
all members of the target population have an equal opportunity of being selected
actual sample is selected through the use of the lottery method
explain what systematic sampling is
every nth member of the target population is selected
explain what stratified sampling is
composition of the sample reflects the proportion of people in strata within the target population
explain what opportunity sampling is
researchers select anyone who is willing to take part are available
explain what volunteer sampling is
participants select themselves to be a part of the sample
evaluate random sampling
+ unbiased
- time consuming
(complete list of target population is hard to obtain)
Evaluate systematic sampling
+ the researcher has no control over who is chosen
- Time consuming
Evaluate stratified sampling
+ easy to make generalisations
- complete representation of target population is impossible
evaluate volunteer sampling
+ More engaged participants
- attracts people who are people pleasers and therefore there are demand characteristics
evaluate opportunity sampling
+ it’s quick and therefore less costly
- researcher bias