sampling - RM

random sampling

where every member of the target population had an equal chance of being selected

Strength of random sampling

The best sampling method for being representative, researcher can not be bias as they have no influence over who is selected

Weakness of random sampling

Sample may still be unrepresentative, especially if sample is too small

opportunity sampling

obtaining people who are available at a certain location at a certain time to just take part

Strength of opportunity sampling

Easier and more convenient sampling method, it takes less time, money and resources required with this method

Weakness of opportunity sampling

Sample is not likely to be representative, population tend to be drawn from one specific area

volunteer sampling

people not selected by the researcher, they are self-selected

Strength of volunteer sampling

Easier and more convenient, requires minimal input from researcher, and uses less time, money and resources

Weakness of volunteer sampling

Not likely to representative, as this sampling may attract a certain ‘profile’ of person who tends to be interested in psychology, helpful, keen and curious

systematic sampling

where every nth member of the target population is selected and placed in different conditions

Strength of systematic sampling

Convenient if the sample is small and is also very objective once the system has been established

Weakness of systematic sampling

It is difficult if the population is large and may be unrepresentative, due to possible bias from research on how the list is organised