Statistics is the study of the collection, organization, analysis, interpretation, and presentation of 
data. It deals with all aspects of this, including the planning of data collection in terms of the design of 
surveys and 
experiments.
A 
statistician is someone who is particularly well versed in the ways of thinking necessary for the successful application of statistical analysis. Such people have often gained this experience through working in any of a 
wide number of fields. There is also a discipline called 
mathemtical statistics that studies statistics mathematically.
The word 
statistics, when referring to the scientific discipline, is singular, as in "Statistics is an art."This should not be confused with the word 
statistic, referring to a quantity (such as 
mean or 
median) calculated from a set of data, whose plural is 
statistics ("this statistic seems wrong" or "these statistics are misleading").