Sample selection and techniques Flashcards
1
Q
What is a random sample?
1
A
- Random technique, everyone in target pop has equal chance of being selected
2
Q
What is the main pro of a random sample?
1
A
- Unbiased, = chance of being selected
3
Q
What are the cons of a random sample?
2
A
- Takes time (list of all target, identify sample, contact)
- Not all ppt agree to take part (volunteer sample) in final sample
4
Q
What is a stratified sample?
1
A
- Ppt selected from different subgroups (age) in target pop in proportion to subgroup fq
5
Q
What is the main pro of a stratified sample?
1
A
- > Ext variables, subgroups = according to important variables
6
Q
What are the cons of a stratified sample?
2
A
- Decision on subgroups to use = bias >generalisable
- Lengthy process, ppt may not agree to take part
7
Q
What is main pro of a volunteer sample?
1
A
- Easy way to find willing ppt, ^compliance
8
Q
What are the cons of a volunteer sample?
2
A
- Bias, extroverts, highly motivated
- Demand characteristics, ^willing, guess aims of study
9
Q
What is the main pro of an opportunity sample?
1
A
- Convenient, takes >prep (find location)
10
Q
What are the cons of an opportunity sample?
2
A
- > representative, drawn from >portion of target pop
- Ppt refuse to take part, final sample = DemandC
11
Q
What is a volunteer sample and an example?
1
A
- Ask ppt willing to take part e.g. newspaper
12
Q
What is an opportunity sample?
1
A
- Select those easily available at the time of study
