MR topic 7

what is population

the entire group of elements with common characteristics relevant to the research

what is a sample?

a subswt of the population selected for the study

what is a consensus?

data collected from every element of the population

what are statistics?

measurements from a sample used to estimate population parameters

5 steps in the sampling design process?

1. define target population

2. determine sampling frame

3. choose sampling technique

4. decide sample size

5. execute sampling

what is the target population?

the group that has the information the researcher needs

what is a sampling frame?

a list or database of the population

why is defining the target population important?

ensures the correct people are included in the study

what is non-probability sampling?

sampling where not everyone has a known chance of selection

main disadvantage of non-probability sampling

cannot generalise results to the population

what is convenience sampling?

selecting people who are easiest to access

advantage of convenience sampling

cheap and fast

disadvantage of convenience sampling

highly biased on not representative

what is judgemental sampling?

researcher selects participants based on their judgment

disadvantage of judgmental sampling

subjective bias

what is quota sampling?

sample reflects population proportion (e.g. gender)

key feature of quota sampling

use quotas + convenience selection

what is snowball sampling?

participants refer to others

when is snowball sampling used?

in hard to reach populations

what is probability sampling?

everyone has a known and equal chance of selection

main disadvantage of probability sampling

results can be generalised

what is simple random sampling?

random selection where all have equal chance

example of simple random sampling

lottery system

what is systematic sampling?

selecting every nth element

what is stratified sampling?

dividing population into groups and sampling each

advantage of stratified sampling

more representative

what is cluster sampling?

dividing population into clusters and sampling clusters

advantage of cluster sampling

cost-effective

what is sample size?

number of elements in each sample

what affects sample size?

• research type

• budget

• accuracy needed

• number of variables

relationship between sample size and accuracy

larger sample = lower error

who collects data in research?

fieldworkers/interviewers

what is selection of fieldworkers?

choosing suitable people to collect data

why is training important?

ensures consistency and reduces bias

what does training include?

• contacting respondents

• asking questions

• probing answers

• recording data

• ending interviews

what is supervision?

monitoring fieldworkers

purpose of supervision

ensure quality and prevent cheating

what is validation?

checking interviews are real

how is validation done?

re-contacting 10-25% of respondents

what is evaluation?

assessing fieldworker performance

criteria of evaluation

• cost/time

• response rate

• data quality

difference between probability & non-probability sampling

PROBABILITY —> random, can generalise

NON-PROBABILITY —> non, random, cannot generalise

which sampling is MOST representative?

stratified sampling

which sampling is CHEAPEST & FASTEST

convenience sampling

which sampling is used for hard-to-reach groups?

snowball sampling