Samplin Flashcards
Random sampling
–
each person has an
equal chance of being
selected e.g. picking
names from a hat.
Random sampling advantage
Very fair as everyone has an equal chance
of being picked unlike opportunity
sampling where participants must be
present to be picked.
Less chance of a bias sample as you are
more likely to get a fair representation of
the target sample
Random sampling disadvantage
Not guaranteed all participants would want
to take part, people may be picked but then
refuse to take part.
Time consuming to get everyone’s name in
the sample frame and then to conduct a
random sample. Unlike volunteer sampling
which is quick and easy to obtain.
Types of sampling
Random sampling
Stratified random sampling
Volunteer sampling
Opportunity samoling
Snowball smpling
Stratified random sampling
sorting the
individuals into groups
e.g. by gender or age
before choosing a
proportional amount
randomly from each
group.
Stratified random sampling advantage
Effective as it allows the researcher to
control the variables that are important
to the research. Means the research is
more scientific and reliable.
Very representative as it reflects target
populations with regards to proportions
of different groups. E.g. If there are 30%
blonde people in the country there would
be 30% blonde people in your sample.
Stratified random sampling disadvantage
More complex and not practical as the sampling frame does not contain the information required to split the population into groups – so you would have to spend time attempting to work things out. Very time consuming as you must find the exact proportions of certain groups and may take long to obtain the exact numbers needed.
volunteer sampling
individuals come forward to take part in the research e.g. in response to an advert.
volunteer sampling adavantage
Quick, easy and cheap to conduct as you wait for replies – usually just the cost of an advert. Participants more likely to consent as they have come forward themselves forward so avoids the ethical issue of lack of informed consent.
volunteer sampling disadvantage
Volunteer bias (bias sample) – only a certain personality will every put themselves forward so it may not be representative of all groups in society. May be hard to gain access to certain participants especially when conducting research on certain subject matters e.g. domestic violence
opportunity sampling
– participants who are both accessible & willing to take part are targeted.
opportunity sampling advantage
No sample frame is needed as it is dependent on somebody people available at a specific time and place e.g. town centre. Very quick, easy and convenient to get a sample unlike random sampling which would take a longer period of time
Opportunity sampling disadvantage
Not everyone has an equal chance of being selected as only those who are there can be selected, unlike random sampling which is fair to everyone. Not representative as all the people available at that moment in time may be from a specific group e.g. all female
snowball sampling
where one participant refers the researcher to another potential participant so the sample gradually gets bigger. E.g. employees from a conveniently located employer near the laboratory could be selected for the sample group
snowball sampling advantage
Useful way to contact sample of people who might be difficult to find or persuade to take part e.g. criminals. No sample frame is needed as it is dependent on who you are referred to by current participants
