ABSTRACT
A sample which is not representative of the population is described as biased. The whole process of sample selection must be aimed at minimising bias in the sample. A sample is selected from the population. The use of the term population makes obvious sense when dealing with communities of people for instance when referring to the population of Britain or the population of London. A sample which is not representative of the population is described as biased. The quota-sampling method can only be used when background information on the target population is known as with community surveys. The respondents to a mail survey form a sample, but it is not randomly selected but self-selected. The problem of achieving randomness can be examined in the case of a household survey of the adult residents of a country. The nearest thing to it would be the electoral registers of all the constituencies in the country.
