Depending on contexts, "statistics" and its derivations can be used in different way:

• numerical data in an area : “sales statistics”, “population statistics”,
• activities of an organization or a country concerning the information of the areas related to this organization or this country, for example rice production, meat consumption, number of students. In this aspect, main statistical activities are collecting, analyzing, synthesizing of data.
• methods used in activities concerning data like sampling methods, evaluation method, interfering methods.
• science that studies problems concerning data. One of the main topic of this science is the study about the variation, the uncertainty of data. The main foundation of statistical science are mathematics and theory of probability.

From these examples, we can recognize that all of the aspects concerning “statistics” have the common object: DATA. So we can define "statistics" as the following (Tamhane, Ajit C. & Dorothy D. Dunlop):

"Statistics is the science of collecting and analyzing data for the purpose of drawing conclusion and making decision."

Depending on activities realized, we can classify statistics as two types:

• Descriptive statistics : used to "describe" the data. Main activities of this type is:
  • collection
  • rearrangement
  • organizing
  • synthesizing
  • presentation
• Inferential statistics : used to analyze, interpret data. Main activities of this type is:
  • analyzing
  • evaluation
  • interpretation

Sometimes, the boundary between these types is not clear, some forms of data synthesizing can be considered as analyzing.