Tossing a coin, winning the lottery, or rolling a die are random events. However, random events have certain patterns, which can be studied and predicted, using probability theory.[2][3][4][5][6]
Scientists can use probability theory to obtain information about things that would be too complex to deal with,[2][3][4][5][6] like statistical mechanics.[7][8][9] Also, scientists discovered (in the 20th century) that atoms, and everything that we know, obeys something called quantum mechanics,[10][11][12] which uses lots of probability theory.