Теорема Байєса

Let's talk about the Bayes theorem!

What is it?

The theorem helps figure out the probability that one event will happen, considering that another statistically related one happened.

I strongly believe that everything is clear only with examples, so let's move to an example.

Example:

Let's assume that we have a box with red and green balls. There are 600 red balls and 900 green balls. We know that among all balls, 5% of red balls have a defect and 20% of green balls have a defect too. Randomly we pulled out a ball with a defect, calculate the probability that it relates to the red ones.

It should be noted that this theorem is widely used in the data science; therefore, look to the general formula: