### Probability theory

You calculate probabilities with the definition of Laplace.

##### Explanation

Suppose you have two coins with which you are going to toss. Each piece has a head (H) and a tail (T) side. After you have thrown them both you can get 4 different combinations.

HH

HT

TH

TT

For each combination, the probability is the same, and so is 1/4. If we make no difference between HT and TH we can conclude that the following probabilities arise

HH = 1/4

TT = 1/4

HT or TH = 2/4

If you have a large number of throws, and then think of some billions, it turns out that this is fairly correct.

## HistoryThe French astronomer Pierre-Simon Laplace (1749 - 1827) contributed a great deal to the calculation of probability. |