Sample selection and techniques

Question 1

What is a random sample?

1

Answer 1

• Random technique, everyone in target pop has equal chance of being selected

Question 2

What is the main pro of a random sample?

1

Answer 2

• Unbiased, = chance of being selected

Question 3

What are the cons of a random sample?

2

Answer 3

• Takes time (list of all target, identify sample, contact)

- Not all ppt agree to take part (volunteer sample) in final sample

Question 4

What is a stratified sample?

1

Answer 4

• Ppt selected from different subgroups (age) in target pop in proportion to subgroup fq

Question 5

What is the main pro of a stratified sample?

1

Answer 5

• > Ext variables, subgroups = according to important variables

Question 6

What are the cons of a stratified sample?

2

Answer 6

• Decision on subgroups to use = bias >generalisable

- Lengthy process, ppt may not agree to take part

Question 7

What is main pro of a volunteer sample?

1

Answer 7

• Easy way to find willing ppt, ^compliance

Question 8

What are the cons of a volunteer sample?

2

Answer 8

• Bias, extroverts, highly motivated

- Demand characteristics, ^willing, guess aims of study

Question 9

What is the main pro of an opportunity sample?

1

Answer 9

• Convenient, takes >prep (find location)

Question 10

What are the cons of an opportunity sample?

2

Answer 10

• > representative, drawn from >portion of target pop

- Ppt refuse to take part, final sample = DemandC

Question 11

What is a volunteer sample and an example?

1

Answer 11

• Ask ppt willing to take part e.g. newspaper

Question 12

What is an opportunity sample?

1

Answer 12

• Select those easily available at the time of study