# Sampling

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Sampling Carrying out a survey of every single potential consumer (known as population) of a firm's product would be impractical, time-consuming and costly. Businesses still, however, need to collect enough primary data to have a clear idea of the views of consumers. This can be done by taking a sample of the population. This sample group should be made up of consumers that are representative of all potential buyers of the product. There are a number of ways in which a sample can be chosen. Random Sampling This method gives each member of a group an equal chance of being chosen. In other words, the sample is selected at random, rather like picking numbers out of a hat. Today computers can be used to produce a random list of numbers which are then used as the basis for selecting a sample. Its main advantage is that bias cannot be introduced when choosing the sample. However, it assumes that all members of the group are the same (homogeneous), which is not always the case. A small sample chosen in this way may not have the characteristics of the population, so a very large sample would have to be taken to make sure it was repetitive. It would be very costly and time consuming for firms to draw up a list of the whole population and then contact and interview them. One method sometimes used to reduce the time taken to locate a random sample is to choose every tenth or twentieth name on a list. This is known as systematic sampling. It is, however, less random. Stratified Random Sampling This method of random sampling is often preferred by researchers as it makes the sample more representative of the whole group. The samp... ... middle of paper ... ... a street within a city may be chosen and then a particular household within a street. Snowballing This is a highly specialised method of sampling. It involves starting the process of sampling with one individual or group and then using these contacts to develop more, hence the 'snowball' effect. This is only used when other sampling methods are not possible, due to the fact that samples built up by snowballing cannot be representative. Firms operating in highly secretive businesses such as the arms trade may use this method of sampling. Similarly, firms engaged in producing highly specialised and expensive one off products for a very limited range of customers may need to rely upon snowballing when engaged in market research. Examples might include firms engaged in nuclear and power generating industries.