Sampling

Question 1

what is a population

Answer 1

a group of people who are the focus of the researcher interest

Question 2

what is a sample

Answer 2

a group of people who take part in a research investigation
- sample drawn form a target population and is representative of the population

Question 3

what is a random sample

Answer 3

All members of a target population have an equal chance of being selected
1. list all members of the target population
2. all members assigned a number
3. sample selected though a lottery method

Question 4

what is a systematic sample

Answer 4

where every nth member of the population is selected
1. a sampling frame is produced (list of people in the target population organised in some order)
2. a sampling system is nominated (eg every 6th person)
3. researcher then works through the sampling frame until sampling is completed

Question 5

what is a stratified sample

Answer 5

• composition of the sample reflects the proportion of people in certain stratas within the target population
  1. identifies the strata that makes up the population
  2. proportions needed for that sample are worked out
  3. participants that make up each stratum are selected using random sampling

Question 6

what is an opportunity sample

Answer 6

• selects anyone who is willing and available

Question 7

what is a volunteer sample

Answer 7

participant selects themselves to be a part of the sample

Question 8

evaluation of random sample

Answer 8

1. potentially unbiased
   - confounding or extraneous variables are equally divided between the different groups enhancing the validity
2. difficult and time consuming to conduct as complete list of target population may be hard to obtain
3. sample may still be unrepresentative as selection is random

Question 9

evaluation of systematic sample

Answer 9

1 . objective
- once the system for selection had been established the researcher has no influence over who is chosen
2. time consuming

Question 10

evaluation of a stratified sample

Answer 10

1. representative sample
   - generalisation is possible

Question 11

evaluation of opportunity sample

Answer 11

1. convenient
   - less time costly as the list of whole population is not needed
   -2. suffers form researcher bias
   - unrepresentative of the target population

Question 12

evaluation of a volunteer sample

Answer 12

1. easy
   - minimal input from the researcher
   - less time consuming
   - participants are more engaged as self selected
2. volunteer bias
   - may attract a certain profile of a person