When data of study is interpreted, it should be distinguished that the data belong to the population or the sample. The average of the data of the population is called the parameter and the average of the data of the sampling is defined as the statistic. Scientific researches generally start with a research question on population parameters, and the current data of the research in the future are collected from the sample and they are evaluated as sample statistics.
Parameter; is the numerical value that describes the population. Statistics are the numerical value that describes the sample. The parameters and statistics can be obtained by a measurement carried out on the population or the sample, as well as a series of measurement results.