In this paper we will study the granular structure of data in the language of rough set theory. It is shown That the granularity of data can be represented in a form of a flow graph, and the relationship between granules obeys Bayes' theorem. This leads to a new method of data analysis.
Motto: "It is a capital mistake to theorize before one has data" Sherlock Holmes" In: A SCandal in Bohemia This paper is dedicated to the renowned Mr. Sherlock Holmes for his mastery in theorizing about data.