Sampling /Sampling Techniques

Question 1

what are the different types of sampling?

Answer 1

• opportunity sample
• random sample
• stratified sample
• systematic sample
• volunteer sample

Question 2

what is an opportunity sample?

Answer 2

recruiting people who are most convenient/most available

Question 3

what is a random sample?

Answer 3

participants are randomly selected using random techniques
- lottery method (names out of a hat)
- random number table
- random number generator

Question 4

what is a stratified sample?

Answer 4

subgroups within a population are identified (age, gender etc), participants are obtained from each subgroup in proportion to occurence in population

Question 5

what is a systematic sample?

Answer 5

use predetermined system to select participants, numerical interval is applied constantly

Question 6

what is a volunteer sample?

Answer 6

advertise on a newspaper/noticeboard/internet

Question 7

what is a strength of opportunity sample?

Answer 7

easiest method because you find first suitable participants you can find, less time to locate sample

Question 8

what is a limitation of an opportunity sample?

Answer 8

biased because sample is drawn from small population

Question 9

what is a strength of random sampling?

Answer 9

unbiased, all member of population have equal chance of being selected

Question 10

what is a limitation of random sampling?

Answer 10

need to have a list of all members of the population then contact those selected, takes time

Question 11

what is a strength of stratified sampling?

Answer 11

likely to be more representative than other sampling methods because there is a proportional and randomly selected representation of subgroups

Question 12

what is a limitation of stratified sampling?

Answer 12

very time consuming to identify subgroups, then randomly select participants and contact them

Question 13

what is a strength of systematic sampling?

Answer 13

unbiased as participants are selected using an objective system

Question 14

what is a limitation of systematic sampling?

Answer 14

not fully unbiased unless you select a number using a random number method and start with this person and then select every nth person

Question 15

what is a strength of volunteer sampling?

Answer 15

gives access to variety of participants which may make sample more representative and less biased

Question 16

what is a limitation of volunteer sampling?

Answer 16

may be biased as participants are likely to be more highly motivated and/or with extra time on their hands
- results in volunteer bias

Question 17

What is quota sampling?

Answer 17

• Work out main demographic characteristics of your population and ensure that your sample is a fairly accurate scaled down vision of the population ‘
• is not random
• researcher aides on now many people are going to represent each category and find the right number of people until quota is filled

Question 18

What is snowball sampling?

Answer 18

• researcher selects key individuals and these contacts greate more contacts and so on
• used when other sampling techniques would be ineffective

Question 19

What is cluster sampling?

Answer 19

-‘Clusters’ or participants are randomly selected and auto individuals within me cluster participate in the research
- multi stage sampling is a form of Auster sampling where 2 random samples are selected, stage 1: selects clusters, stage 2: p’s within clusters are randomly selected

Question 20

what does the term ‘target population’ refer to?

Answer 20

all members of a group you are interested in studying

Question 21

what is a sample?

Answer 21

a smaller group selected from all the people in your chosen target population

Question 22

what is generalisation?

Answer 22

• ability to generalise findings
• ability to apply findings beyond particular individuals studied

Question 23

what is sampling bias?

Answer 23

when the sample does not have generalisability and external validity e.g. sample not randomly selected

Question 24

what factors may create sampling bias?

Answer 24

• often difficult to recruit participants and may have to be bribed in some way
• sometimes force/coercion is used
• some participants will volunteer for various reasons

Question 25

what sampling techniques are non-probability samples (vulnerable to sample bias)?

Answer 25

• opportunity
• volunteer
• quota
• snowball

Question 26

what sampling techniques are probability samples (avoids researcher bias in sample selection)?

Answer 26

• random
  stratified
• systematic
• cluster