sampling Flashcards
(12 cards)
5 types of sampling
random
stratified
opportunity
volunteer
systematic
random sample
every person from a target population has an equal chance to be picked - lottery method and randomly picked
+/- random sample
potentially unbiased - EVs/CVs controlled
time consuming - need a list of entire target pop
systematic sample
pps selected using a set pattern - every nth person selected
+/- systematic sample
unbiased - first item selected at random
time consuming - need entire list of target pop
stratified sample
reflects percentages of subgroups in entrie populations - these percentages will be the same in the study
+/- stratified samples
representative - generalisability
not perfect representation - people act differently
opportunity sample
people who are easiest to obtain will take part - obtained through asking nearby people
+/- opportunity sample
quick and cheap
biased - cant generalised to population
volunteer sample
pps select themselves through adverts or offering
+/- volunteer samples
pps are willing - high engagement
volunteer bias - pps may share traits - they volunteered
