The word statistics while referring to a scientific discipline should not be confused with the word statistics referring to a quantity like mean or median calculated from a set of data as given in the example.
Statistics is all about collection, organization and analysis of data and making interpretation.
To study a population or process, we collect the required data showing the characteristics of the process. It may not be practically possible to collect the entire set of data. Then, a chosen subset of the population called a sample is studied. Sample should be a representative sample. This data can then be subjected to statistical analysis, serving two related purposes: description and inference.