Internet users across the globe increasingly rely on social media sites like Facebook, Twitter and other social media websites to receive news and update on daily and major events from other people , companies and organizations. These posts can be biased about a product or a service or a company and thus, affecting the marketability of a product/service, or the outcome of an event. Analysing the sentiment of people’s posts on a certain topic without detecting the bias can lead to cognitive bias error on predicting the outcome of an event. Twitter is one of the most popular websites that has an extremely large user base. It is also a popular platform that researchers use to perform sentiment analysis or to make predictions.