User Sampling Methods :: essays research papers

1Sampling MethodsWhen surveying, for any purpose, it is important to recognise that the results atomic number 18 only as representative as the survey subjects (the sample), and as such much academic research has been performed in to techniques for weft, broadly placing them in one of two categories probability sampling and non-probability sampling.In short, with probability sampling the participants atomic number 18 selected by occur. There are dozens of methods of selecting members, using a variety of mathematical techniques, but the key is that each subject has a random, calculable chance of being selected. There is no human intervention involved in the selection.MethodCharacteristicsSimple (random) SamplingThe sample is selected entirely at random stratifyThe population is first divided in to exclusive subgroups based on some predetermined criteria (e.g. location), then samples are selected at randomProportionate secernateAs above, but a smaller group that would otherwise n ot provide statistically valid results may be oversampled then the results weighted to change by reversal for this. For example, if a particular group is too small to provide a statistically significant sample, more members of that group would be sampled ClusteringThe starting foreland for the sample is randomised, then assumes that the sample at that point is representative of the region. For example, selecting a street corner, interviewing the first 10 people, and assuming that they are representative of the area duck 2 - Probability Sampling MethodsNon-probability samples, however, contain an element of human bias in the sample selection. Again, there are various methods for the selection, the most common of which areMethodCharacteristicsQuotaRespondents are preselected to ensure that the sample is representativePurposiveSubjects are selected as they have some specific characteristic, for example, hold a certain view or job typeConvenienceThe sample is selected by availability SnowballingContacts provide information about other potential respondentsSelf-selectionRespondents volunteer themselves for selection apprehensionAn expert uses his or her judgement to nominate people for sampleTable 3 - Non-probability Sampling MethodsMost samples use a combination of sample selection methods. For example, quota sampling is often used to ensure that a random sample is actually representative of the population.2Survey typesThere are three fundamental surveying techniques that are suitable for consideration in the projectInterviewTelephoneSelf Administered Survey2.1Interview (face to face)This category includes in-depth interviews, focus groups and projective methods (such as intelligence agency association tests) which are not suitable for use in this project. There are several distinct advantages to this type of survey, such asResponse pass judgment tend to be higher than other methods Ability to reassure the subject about their responses