Sampling Flashcards
`samples have to be R…. for a T… population
Representative / Target
what does representative mean?
someone/something who speaks or does something officially for another person or group of people
what does sample mean?
A small part of a quantity intended to represent a large amount.
what is target population?
this is the group of individuals that the researcher is interested in.
The sample should be representatives so the generalization about the target population can be made on the basis of the sample.
what is a opportunity sample and the benefit of it?
to do this you find the people most readily available, e.g people walking down the street/people in the common room.
it is the easiest sampling method because you use the first participants you find, which means it takes less time to locate your sample than using one of the other techniques.
opportunity sample is inevitably what?
it is inevitably biased because the sample is drawn from a small part of the target population
the opportunity sample is inevitably biased, how do we avoid this?
to avoid this, the researcher could go at certain times of the day in order to get certain people
what is volunteer sample and the benefit of it?
to do this type of sampling, you have to advertise on a notice or a newspapers.
This is good because you have access to a variety of participants (e.g all the people who read a newspaper)which would make the sample more biased and representive
however, the volunteer sample still can be considered to be biased and unrepresentative, why?
this is because only people who read the newspaper will respond to the advents, they likely to be more highly motivated and with more extra time on their hand.
what is random sample?
this means each number of the population has an equal chance of being selected.
the easiest way to do this is to give each participant a number or draw names out of hat and allocate these to the conditions.
it is sometimes called the lottery method.
what is the benefit of the random sample?
it is good because it is unbiased
what is weakness of the random sample?
if the population is too small, it may cause the sample to be bias
what is a systematic sample?
this means taking every nth person from a list.
calculate population size,decide what size sample you want and what sampling interval will be.
what is a weakness of systematic sampling?
you can miss key characteristics of other participants
what is stratified sampling?
divide up population based on characteristics important to research, age,gender, etc.
randomly sample from each strata.
put all names in a hat and draw a out the number of names needed
what is a weakness of stratified sampling?
it is very time consuming
what is a strength of stratified sampling?
it is very representative of the target population.
also there is no reashere bias as sample is chosen at random.
