Managament accounting

Cluster sampling is a non-random sampling method that involves selecting one definable subsection of the population as the sample, that subsection taken to be representative of the population in question. For example, the pupils of one school might be taken as a cluster sample of all children at school in one county.

Advantages: 1) It is a good alternative to multistage sampling if a satisfactory sampling frame does not exist. 2) It is inexpensive to operate.

Disadvantages: There is potential for considerable bias.

A non-probability sampling method is a sampling method in which the chance of each member of the population appearing in the sample is not known.

In quota sampling, randomness is forfeited in the interests of cheapness and administrative simplicity. Investigators are told to interview all the people they meet up to a certain quota.

Advantages: 1) It is cheap and administratively easy. 2) A much larger sample can be studied, and therefore more information can be gained at a faster speed for a given outlay than when compared with a fully randomized sampling method. 3) Although a fairly detailed knowledge of the characteristics of a population is required, no sampling frame is necessary because the interviewer questions every person they meet up to the quota. 4) It may be the only possible approach in certain situations, such as television audience research. 5) Given suitable, trained and properly briefed field workers, quota sampling yields enough accurate information for many forms of commercial market research.

Disadvantages: 1) The method can result in certain biases. For example, an interviewer in a shopping center may fill the quota by only meeting people who can go shopping during the week. 2) The non-random nature of the method rules out any valid estimate of the sampling error in estimates derived from the sample.

Once data have been collected, they need to be presented and analyzed. It is important to remember that if data have not been collected properly, no amount of careful presentation or analysis can remedy this defect.