Four common sampling methods

Sampling is an important method in statistics, which can infer the characteristics of the population through the analysis of samples. This paper will introduce four common sampling methods, including simple random sampling, periodic systematic sampling, stratified sampling and cluster sampling.

simplerandom sampling

Simple random sampling is a sampling method to ensure that everyone has an equal opportunity to be sampled. It can be achieved by drawing lots, rolling dice or consulting a random number table. Although the error of this method is small, the operation is complicated.

Periodic systematic sampling

Periodic systematic sampling is a sampling method of taking samples in turn according to the principle of equidistant. It can determine the first item by simple random sampling, and then take samples in turn according to the principle of equidistant. This method is particularly simple when sampling on the pipeline, but once the starting point is determined, the whole sample is fixed.

Stratified sampling method

The stratified sampling method is suitable for people who can be divided into different subgroups. Individuals are randomly selected from each layer according to the specified proportion. This method has the advantages of good representativeness and small error, but the operation is relatively complicated and is often used for product quality inspection.

Cluster sampling method

Cluster sampling method divides the population into several groups, and then randomly selects several groups, and the sample consists of all individuals in these groups. Although this method is simple to implement, the samples are mainly from individual groups, which is poor in representativeness and has a large error.