sampling methods Flashcards
sample
the group of people who are selected from a population to take part in an investigation
aim of sampling
to ensure that the sample is representative of the target population so that results can be generalised to all of them
sampling method
the process of selecting participants to take part in studies
target population
- the group of people from whom the sample is taken
- in some cases, the largest group to which results can be generalised
generalisability
to be able to accurate take a research finding and apply it to a larger population
population validity
the extent to which the results can be generalised to groups of people other than the sample of Ps used
random sampling
- every member of the population has an equal chance of being chosen to participate in the research
- this involves identifying everyone in the target population and then selecting the number of Ps you need in a way that gives everyone an equal chance of being picked, such as names into a hat, using a random name generator
strengths of random sampling
- it provides an unbiased and fairly representative sample of the target population
- the sample is less likely to include outliers
weaknesses of random sampling
- it can be very time consuming and labour-intensive
- itt is impossible to carry out if you do not have the names of all the people in your target population (e.g. people with depression - there are so many that it would be prohibitive to use this method)
opportunity sampling
taking a sample of people who are available at the time that the study is being carried out and fit the criteria of the research
strengths of opportunity sampling
- it is the most practical method in terms of time, effort and therefore money
- this will allow for a larger number of Ps to be studied, which will increase the population validity of the study
weaknesses of opportunity sampling
- it can be biased
- it is easy for the researcher to select people from their own social/cultural groups, or for specific times of people to be available at the right time and place
- so the sample would not be representative the whole target population, as the sample may be skewed
volunteer sampling
Ps become a part of the study because they volunteer when asked, or they respond to an advert
strengths of volunteer sampling
- it can be fairly quick and easy in comparison to random sampling
- it allows for a wide variety of Ps to be reached, making the sample more likely to be representative of the target population, so generalizable and having greater population validity
weaknesses of volunteer sampling
- the type of Ps that put themselves forward may be more motivated to be involved in the research than those who do not volunteer, so the sample might not be representative of the general population
- there may be a greater number of outliers and social desirability biases shown