L6 - Sampling Techniques & Pilot Studies Flashcards
1
Q
Target population
A
- group researchers are studying and want to generalise results to
E.g. all females aged 20-30 who shop online - sampling techniques are used to obtain sample of target population - can avoid studying whole population as would take too long and be too expensive
2
Q
Sample
A
Should be representative of population from which it’s drawn and should have the same characteristics as population
E.g. reflect social classes/ethnicities etc…
3
Q
Random sampling
A
- every member of target population has same chance of being selected
- place population names in had then select sample
e.g. first 20 names chosen out of 100
4
Q
Advantages of random sampling
A
- if target population is large and large sample is chosen then it’s likely sample will be representing so results can be generalised from sample to target population
- no researcher bias when selecting sample, as it’s been chosen by chance without any conscious choice from researcher - equal chance of being chosen
5
Q
Disadvantages of random sampling
A
- can be difficult to get full details of a target population from which to select a sample
E.g. getting women aged 20-30 may be hard as some not registered/in prison
6
Q
Systematic sampling
A
- Participants selected by taking every Nth person from a list
E.g. make list of total population then choose every 6th person to be part of sample
7
Q
Systematic sampling advantages
A
- simpler then random sampling as it only needs a list of target population then the researcher chooses every nth person - random sampling needs more time/effort (writing names on slips etc..)
8
Q
Systematic sampling disadvantages
A
- selection process can interact with hidden periodic trait within population, if selection coincides with periodicity of trait then it would no longer be random
- not all members of target population who are selected will be available/willing to take part - could make sample unrepresentative, some may refuse to take part, reduces size dramatically
9
Q
Stratified sampling
A
- classifying population into categories and then randomly choosing sample consisting of participants from each category in same proportions as in population
- population divided into strata in terms of characteristics e.g. age, gender etc…
10
Q
Stratified sampling advantages
A
- all groups in population included so it should be representative of population
11
Q
Stratified sampling disadvantages
A
- Can be very time consuming as categories have to be identified/calculated, if you don’t have details of all people in target population/relevent strata it would be harder to conduct sample
12
Q
Opportunity sampling
A
- select participants who are readily available and willing to take part
- known as convenience sampling - select participants as it’s convient to do so
- may have easy access to a group of people they know well/have regular contact with
13
Q
Opportunity sampling advantages
A
- Easiest and most practical method
- especially compared to stratified sampling which may be expensive and time consuming
14
Q
Opportunity sampling disadvantages
A
- High chance it won’t be representative of target population
- sometimes people feel obligated to take part in research (esp. if they know person) even if they don’t want to - this is unethical
15
Q
Volunteer sampling
A
- people volunteer to participate in study - researcher usually advertises for people to take part through leaflets, posters, radio or TV broadcasts
- means people take notice of info and then can decide if they would like to take part in research and volunteer time