Research Methods P2 Flashcards
(41 cards)
What is sampling?
Various ways in which researches select pps for study
What is the target population?
Specific group of people from whole population you want to study
What is a sample?
Smaller group you actually select from target population to participate in the study
What is volunteer sampling?
- Pps not directly asked
- Self select to take part
e.g. Placing advert in newspaper
What is systematic sampling?
- Sample frame produced
- Choose nth person until sample size met
e.g. List alphabetically then every 5th person
What is opportunity sampling?
- Researcher asks who readily available
e.g. Directly asks student in group
What is stratified sampling?
- Composition reflects proportion of subgroups
- Strata identified the % proportion calculated
- Random sampling done on each strata
e.g. 60% male 40% female= 6:4
What is random sampling?
- Obtain lists then chosen by chance
e.g. Random computer generator
How is random sampling representative?
P= Representative
E= No control over who selected
E= Improve population validity
Why can random sampling be difficult/ time consuming?
P= Difficult + time consuming
E= Need list of target population
E= Not time effective
Why is random sampling not giving you a guaranteed representative sample?
P= Not guaranteed representative sample
E= Groups over represented
E= Less representative than stratified
Why is opportunity sampling data easy to obtain?
P= Easy to obtain
E= Uses anyone readily available
E= Sample not identified prior
How can opportunity sampling be unrepresentative?
P= Unrepresentative
E= Pps readily available
E= Pps share similar background reducing population validity
Why might there be ethical issues surrounding opportunity sampling?
P= Ethical issues
E= Readily available
E= Pps feel pressured
Why may volunteer sampling save time when picking who the ppts are?
P= Locates particularly niche group
E= Advertise for specific group
E= Save time gathering sample
Why does volunteer sampling lack generalisability?
P= Lacks generalisability
E= Uses people who put themselves forward
E= Limits population validity
Why may a volunteer sample not be representative?
P= Not representative
E= Self selected ppts
E= Limits population variables
How does systematic sampling avoid researcher bias
P= Avoid researcher bias
E= No influence over who’s chosen
E= More representative sample
Why does systematic sampling not guarantee a representative sample?
P= Don’t guarantee representative sample
E= Groups over/under represented
E= Better to use stratified
How does stratified sampling avoid researcher bias?
P= Avoid researcher bias
E= No influence over who chosen
E= Representative sample
Why is stratified sampling time consuming?
P= Time consuming
E= Need details from target population
E= Takes time to get all details
How may stratified sampling not be completely representative?
P= Not completely representative
E= Strata cant reflect all subgroups
E= Representation of target population not possible
What are the 4 types of extraneous variables?
- Experimenter effects
- Situational variables
- Demand characteristics
- Investigators effects
Why is putting controls in place to minimise the impact of extraneous variables a good thing?
- Establish greater C+E
- Confident that it is manipulation of IV that causes effect on DV
- Means higher internal validity
