sampling

sampling

1. what is sampling?

   • use sample drawn from larger populations.procedure by ehich participants are selected to take part in a study is called the sampling method.
   • aim of sampling methods is to obtain a group of participants that are representative of the target population
   • representative samples represent the target population and should share the same important characteristics.
   • Target population is the group of people whom the researcher wants to target or generalise the results, in general the larger the sample the better it is.

2. Opportunity-

   • description
     • asking whoever is most easily available and willing to take part at the time of the study
   • advantages
     • convenient in terms of time and cost-easy way to obtain large samples compared to random/startifies sampling. commom forn of sampling
   • disadvantages
     • likely to be biased- researcher influences who is asked to take part, biased when they select ps, select ps to support their hy[pothesis,-findings not generalised to the wider popukation, sample likely to be unrepresentative and lack population validity

3. self-selecting(volunteer)

   • description
     • advertising for volunterrs, individuals decide they wish to be invoved in the study approach the researcher and become volunteers.
   • advantage
     • likely to be motivated to take part -because they volunteered and may have some interset in the research -take it more seriously than participants chosen using other sampling methods-random sampling
   • disadvantage
     • participants are self selected-may differ in important aspects from those who did not volunteer, weakness as ps should be a cross section of different people as in stratified sampling. unlikely that the volunteer sample will be representative of the target population.

4. systematic

   • description
     • selecting the nth person on a a list-choose n by dividng the population size by the sample size
   • advantage
     • researchers selction of ps is not biased by preconceptions of the ps abilities or behaviour unlike in oppurtunity sampling.
   • disadvantage
     • paricipant may refuse to take part, researcher might end up wit a small sample or cost time and money to select ps, choosing every nth person might mean tthat researcher ends up with sample dominated by males or females(androcentric/oestrocentric)

5. random

   • description
     • every member of the target population has an equal chance of being selected, selected by putting names of the whole target population in a hat or more commonly with larger samples a computer programme can generate random lists.
   • advantage
     • avoids the possibilty of researchers selecting a sample that supports their hypothesis unlike oppurtunity sampling.-less likely to be biased and have greater population validity
   • disadvantages
     • participants are selected they may not be available or may refus to take part. -researcher will have a small sample or will have to randomly select more ps. - costly and time consuming
     • end up consisting of mainly males or female ps which would make the sample biased

6. startified

   • description
     • ps are randomly selected. evrery member of the target population has an equal chance of selction, this method likely to obtain te most representative sample out of all the methods.
   • advanatges
     • more likely to be representative than those obtained through other sampling methods- volunteer sampling as each sector of the target population is reflected in the sampl-results can be applied to the wider population
   • disadvantages
     • very complex and time-consuming to achieve unlike oppurtunity sampling- decide on which categories of the target population to include in the sample and then calculate the percentages-done on computer

7. types of bias

   • gender bias
     • sample which predominantly male (androcentric) or female (oestrocentric) - sample is bias. if an all-male/female sample is used then we cannot geralise the findings to both genders.
   • culture bias
     • carried out in one culture, findings are applied to other cultures (culturally biased) if the research focuses on one culture and ignores other cultures, seeing them as less important (ethnocentric), study should be conducted in many contries (cross cultural)-generalise the finding to several cultures