sampling techniques

• what is volunteer sampling?

  self selecting

  people who have chosen to take part
• * quick easy cheap for volunteer?

  • researcher just needs to produce an advert/poster for participants - requires minimal effort
  • does not need to find & select people to take part
  • researcher can gather sample much quicker & spend more time on data analysis
• X unrepresentative for volunteer?

  • sample may not represent an entire population as some people who work full time/older aged people may not take part
  • findings cannot be generalised to rest of target population as only certain types of people are involved in research so another method be appropriate
• what is random sampling?

  every member of population has equal chance of being chosen
• * reduced researcher bias for random?

  • researchers may choose certain participants to take part in research provide them with results they desire
  • by selecting participants randomly - removes this possibility & gives everyone an equal/fair chance of taking part
  • researcher's own bias & opinions will not impact sample making it more representativeas everyone has an equal chance of being chosen
• * more likely to be representative for random?

  • by selecting participants randomly it means there will be a more varied selection of participants
  • the wider the variety of different people chosen will mean the results will be more representative of the target population chosen
  • however due to time consuming nature of method researcher may have smaller sample & choose similar types of peeople
  • cannot guarantee that we can generalise findings to rest of target population
• X difficult & time consuming for random?

  • reseacher needs to write all of participants names down on a sheet of paper & place them in a hat to then choose the required amount
  • this will be more time consuming if researcher needs a large sample of people
  • it is a lot less time efficient in comparison to other sampling methods so another method may be more appropriate
• what is oppurtunity sampling?

  reseacher chooses whoever is available at the time
• * quick easy cheap for oppurtunity?

  • researcher may use anyone who is available & willing to take part as it is more convenient
  • quick so researcher can easily get a sample & spend more time on data analysis
• X unrepresentative for oppurtunity?

  • researcher may choose certain people who are available at the time, but does not reflect entire taget population
  • findings cannot be generalised to rest of target population as only certain types of people are involved in research
• what is systematic sampling?

  involves selecting every nth member of target population
• * reduced reseacher bias for systematic?

  • takes control from researcher when selecting participants so that they are less likely to be able to choose participants that they wish to take part
  • results will be free from reseacher bias & sample will be more generalisable to target population as they have not been chosen by researcher themselves
• X not fully representative for systematic?

  • system that has been chosen may be flawed & may mean some participants are more/less likely to be selected than others
  • findings cannot be generalised to rest of target population as only certain types of people are involved in research & certain individuals have been missed from sample
• what is stratified sampling?

  • reseacher must identify sub group (strata) in target population
  • work out what proportion of that target population they represent
  • names are chosen randomly (random sampling)
• * most representative for stratified?

  • by identifying sub strata & then finding participants from each one its most likely to represent each section of the target population by doing random sample after
  • findings can be generalised to whole target population as it has measured participants that are proportionate to target population
• X time consuming & difficult for stratified?

  • it is difficult to find enough participants who are willing to take part for each sub strata & time consuming to also do random sampling
  • not as time efficient in comparison to other methods where there could be more time for other parts of research such as data analysis
• * no researcher bias for stratified?

  • researcher has no input on who to choose for sample as its chosen by a % then randomised further
  • will be no preference/bias from researcher
  • sample will be more representative & results will be more accurate so can be generalised
• * no researcher bias for volunteer?

  • reseacher does not select p themselves
  • so they have to accept people who have volunteered
  • reduces bias that researcher may input in other methods
  • results will not be subject to biased influences so will be more representative of target population