sample

types of sampling

• random

• systematic

• stratified

• volunteer

• opportunity

define random sample and how its conducted

This means that every one in the target population has an equal likelihood of being selected to be in the sample

how = list of everyone in target population then the use random generator

strength of random

• eliminated researcher bias

• normal when done on large enough scale is representative

limitation of random

• by chance could be repsenative

• takes time as need a list of everyone and have to use a random generator

systematic

This is when every n th person from a study is chosen eg every 5th

again list of every one in target population they select very nth member

strength of systematic

• again avoids researcher bias

limitations of systematic

• takes time

• possibility of unrepresentative sample

opportunity

This is a sample who is made up of those who are available

One strength of opportunity

• very fast sample

limitation of opportunity

• the choose the person research bias

volunteer sample

This is the sample goes to researchers

strength of volunteer

• strengths is easy as ps go to them

limitation of volunteer

• suffers from volunteer bias

stratified sample

by selecting from strata characteristic of wider sample are represented

one strength is stratified

• this means highly accurate sample and easy to generalise

One limitation is stratified

not difference can be included so not fully generalisable

takes time