Statistics is the science of the collection, organization, and interpretation of data. It deals with all aspects of this, including the planning of data collection in terms of the design of surveys and experiments. (From Wikipedia)
More specifically, mathematical statistics is the study of statistics from a mathematical standpoint, using probability theory as well as other branches of mathematics such as linear algebra and analysis. (From Wikipedia)
For questions which are more generally about collecting and treating data, it might be advisable to consider posting questions on Cross Validated.