Research Methods: Sampling Flashcards
What does population mean ?
Large group of individuals that a particular researcher may be interested in studying ( students attending sixth form)
What does target population mean ?
Particular subset of the overall population from which the sample will be taken , for example students attending sixth form in Newcastle
What does sample mean ?
Refers to the group of people who take part in research investigation. Drawn from the target population and is presumed to be representative of that population
What does representative mean ?
Contains the same characteristics as the the target population from which the sample was taken
What does generalisation mean ?
The extent at which the findings and conclusions can be broadly applied to the population
What four evaluation points can be used when it comes to sampling ?
Is it representative?
Is there bias involved ?
Time taken
Ease of sampling
What are the methods of sampling
Random Systematic Stratified Opportunity Volunteer
Main point of random sampling ?
Each member of a population has an equal chance of being picked
What is the method of random sampling ?
1) list of all members in target population obtained
2) all names assigned a number
3) sample generated from lottery method
What is main point of systematic sampling ?
Every nth member of the target population is elected
Systematic sampling method
1) sampling frame created (list’ normally people from the target population sorted alphabetically
2)sampling system made based on number of people required
For example : 25 people but you only need 5 so the nth person would be the every 5th person
Stratified sampling main point
Sample reflects the proportion in certain strata within the target population
Stratified sample method
1) identify different strata
2) proportions for sample to be representative worked out
3) participants that make up stratum are randomly selected
In Manchester 40% people support Man City, 40% support man united, 15% support Bolton and t% support Leeds then in a sample of 20, 8 would support Man City, 8 would support man united, 3 would support Bolton and 1 would support Leeds. What kind of sampling is this ?
Stratified
Main point of opportunity sampling ?
Selecting anyone who is willing and available
Opportunity sampling method
The researcher simply takes the chance to ask whoever is around at the time ta the time of their study
Main point of volunteer sample?
Participants selecting themselves to be part of sample
Volunteer sample method
Researcher places an advert in a newspaper or just participants simply raising their hand whenresearcher asks
Strengths of random sampling ?
Free from researcher bias - increases validity
Researcher has no influence
Limitations of Random sampling
Time consuming
Lost of everyone in target population is hard to get
Unrepresentative
Participants refuse to take part
Strengths of systematic sample
Avoids researcher bias
Fairly representative
Limitations of systematic sampling
Time consuming (target population list)
Participants refuse to take part
Still not the most representative
Strengths of stratified sampling
Avoids researcher bias once participants divided in strata they are randomly selected
Most representative
Generalisation of study to target population is possible
Limitations of stratified sample
Very time consuming
People could still refuse to take part
Complete representation is not possible
Strengths of opportunity sample
Convenient
Quick and easy
Saves time and money
Limitations of opportunity sample
Unrepresentative of target pop because it’s from a specific area - a street in town
Same people present at the same time with similar interests
Can’t be generalised to the target pop
Researcher bias - may avoid people they don’t like the like of or the opposite
Strengths of volunteer sample
Easy
Minimal input from researcher
Less time consuming
Limitations of volunteer sample ?
Volunteer bias - people who volunteer are doing it for a reason that might affect how far the findings can be generalised
