Cortana (US) on both Windows Phone 8.1 and Windows 10 for Phones preview have added a new interest. The new interest is called “Entertainment” and if you select it you add “pick the winners” to Cortana’s Notebook.
It seems that in case you are interested in guessing winners of the contests then Cortana may offer you with chance of predicting the winners of prizes right from your phone.
You can read more about Cortana on Windows Phone 8.1 and Cortana for Windows 10 for Phones by clicking here and here.
Thanks @i_jp4