sample

Sample (Sample), a collection of elements extracted from a population. The same population can extract several samples to form a set, such as 1,000 people from 10,000 Beijing citizens, and there areTwo kinds of extraction methods (without repeated sampling), the set of elements obtained by each extraction method is a sample. In the process of obtaining data, we are often limited to human, material and financial resources, and it is impossible to exhaust all the extraction methods to collect data. Researchers usually get one of so many samples. Therefore, the sample is not unique and uncertain for researchers, but once the data of a sample is collected, its characteristics can be characterized by the collected data. Therefore, the characteristics of the sample are known.

A generalized numerical measure that describes the characteristics of a sample is called sample statistics (Statistics), which is some quantities calculated according to the sample data, is a function of the sample. Sample statistics mainly include sample mean., sample standard deviation, sample proportionWait. The number of elements constituting a sample is called sample size or sample size (Sample size), generally usedExpress.