ELI5: Explain Like I'm 5

Compound probability distribution

Okay, imagine that you have a big bag with different kinds of candies in it, and you want to know the probability of getting two specific candies at the same time. This is what we call a compound probability distribution.

A probability distribution means the chance of getting a certain thing out of all the possible outcomes. In this case, the possible outcomes are all the different pairs of candies you could get out of the bag.

Now, to calculate the probability of getting two specific candies together, we need to consider two things. First, we need to know the probability of getting the first candy out of the bag. Second, we need to know the probability of getting the second candy out of the bag after we’ve taken the first one.

Let’s say you have 50 candies in your bag, and 10 of them are red, 20 are blue, and 20 are green. And let’s say you want to know the probability of getting one blue candy and one green candy.

To figure that out, we have to start with the probability of getting the first candy. There are 50 candies in total, so we have a 20/50 or 2/5 chance of getting a blue candy first. Once we take one blue candy out of the bag, there are 49 candies left, with 20 of them being green. So, the probability of getting one green candy after one blue candy is already taken is 20/49.

To get both blue and green candy together in this scenario, we need to multiply the probability of getting one blue candy (2/5) with the probability of getting one green candy after taking the blue candy (20/49). When we multiply these probabilities, we get the compound probability distribution of 8/245, which means there is an 8/245 chance of getting a blue and green candy together.

So, in summary, a compound probability distribution is about calculating the probability of two independent events happening together. This involves figuring out the probability of the first event happening, and then the probability of the second event happening after the first event has already occurred. We then multiply these probabilities to get the compound probability distribution.