sociology SAMPLING

what is probability sampling

every member of the population has a chance at being selected

what is stratified sampling

involves dividing the population into sub populations that may differ in important ways. allows the researcher to get more precise conclusions

what is systematic sampling

similar to random sampling. with every member of the population is listed with a number, but instead of randomly generating numbers, individuals are chosen at regular intervals e.g every 10 people

what is non-probability sampling

individuals are selected based on a non-random criteria and not every individual has a chance at being included

what is convenience sampling

simply includes the individuals who happen to be most accessible to the researcher

what is snowball sampling

people not on a list but recommended by sample participants it grows to other people. this is good for hidden populations

give an advantage and disadvantage of snow ball sampling

builds trust if a participant is referred by a friend

could be bias because a participant is likely to refer someone similar to them

give a strength and weakness of random sampling

everyone has a chance at being picked

reduced bias because they aren’t being picked based on something

more representative

time consuming

needs a full list of the population

not always practical

give a strength and weakness of stratified sampling

ensures key groups are represented

more representative

useful for comparisons

time consuming because of detailed population info

difficult to organise properly

give a strength and weakness of opportunity sampling

quick and easy to carry out

practical in school and classrooms

cheap

highly bias

not representative of the whole population

researcher chooses who takes part

give a strength and a weakness of voluntary sampling

ethical- choose to take part

give detailed answers because they chose

easy to organise

self selection bias

more likely strong opinions

not representative

give a strength and weakness of systematic sampling

simple and structured method

reduces some researcher bias

easier than random sampling.

can be bias if there is a pattern in the list

still not fully random

may over represent certain groups