Data can be represented in the form of tables, graphs or even caselets. Data represented in the form of a table is raw and usually is quite time consuming to process such data.
Analyses such as trends, problem areas, percentage distribution are quite difficult to perform when the data is represented in the form of a table.
Graphs on the other hand represent the same data visually. Graphs offer the luxury of processing data by observation as we can easily see the trends and distribution. Even problem areas are easy to identify by looking at the deviation from the trends.
Representing data in the form of caselets is quite uncommon in the real world. However, it is very popular with car examiners. In this case, date is hidden between paragraphs and you have to unearth the data as you go on reading the paragraph.
This is probably the worst case of data representation when it comes to analyzing and drawing conclusions out of it.