Sampling Flashcards
What is a target population
The group of people the psychologist wants to be able to generalise their findings to
What may problems with generaliseability be
Age bias,only studying people from one area, gender bias or only one ethnic group
What are the 4 methods of sampling
Opportunity sampling
Volunteer sampling
Snowball sampling
Random sampling
What is opportunity sampling
Simply about making use of the people that are readily available to you and willing to participate
What are the strengths of using opportunity sampling
The easiest, quickest and most economical way to obtain participants as the researcher will use people they have easy access to and we don’t have to pay for advertising
also time efficient
What are the weaknesses of opportunity sampling
Likely to produce a biased sample as only certain types of people are selected and due to chance so open to accidental research bias so it isnt very representative. Also the researcher may select people who look more friendly or willing to participate
What is volunteer sampling
People who want to take part in researcher volunteer themselves. The psychologist will place an advert like a poster or TV advert. People interact in this study would reply and the psychologist will filter the responses to collect samples that reflect the target population
What are the strengths of volunteer sampling
Gives a wide range of access to potential participants
Also very convenient and ethical if it leads to informed consent
Volunteers are more likely to commit to the study and be fully involved in the study so reduced order effects
What are the weaknesses of volunteer sampling
Often unrepresentative as it leads to a biased sample people tend to not respond to adverts unless they have a strong interest or motivation to take part There may be inherent bias in the participants as similar types of people may
sign up due to interest/need for money/ experience doing studies. This could
lead to bias
What is random sampling
Every member of the target population has an equal chance to be selected.Researcher needs the names of all members of his TP and all potential participants are entered into a draw. Names are randomly selected until the desired number of participants is chosen
What are the strengths of random sampling
Least biased method as all members of TP have an equal chance of being selected as the psychologist doesn’t collect the sample
What are the weaknesses of random sampling
Very difficult and time consuming to do especially with a larger target population
Not everyone who is picked may consent to take part, meaning it can take a
long time for the experiment to actually begin.
What is snowball sampling
Can be used if your population isn’t easy to contact. Achieved by asking a participant to suggest someone else who may be willing or appropriate for the study. These are paticularly useful in hard to track populations like drug users or truants
What are the strengths of snowball sampling
Possible to include members of groups where no lists or identifiable clusters exist like drug users
What are the weaknesses of snowball sampling
There is no way of knowing where the sample is repretsentative of the populations can however have bias as people’s friends or family are likely to share
characteristics, meaning the sample is not representative of a wide enough
group of people to be accurately representative
