**2.4. Data analysis**

The WEKA software was used offline to analyze data during pre- processing, classification and the post processing. In order to process the data gathered from the Twitter API, the file type or dataset was formatted to a file extension of .arff (attribute file format) and this file extension is generated from a.csv (comma-separated values) file which separates each attribute by a comma. The .arff file is an ASCII text file that describes a list of instances sharing a set of attributes.

A spreadsheet application was another useful tool in the sentiment analysis research conducted. This tool allowed one to inspect the comma-separated values files and also create graphs and tables.
