# How do you calculate marginal, joint, and conditional probabilities from a two-way table?

##### 1 Answer

If you are given a pmf =

and you would like to find the **marginal**

we would use the formula

in other words you would sum over all of

So if we look at this table and want to find the **marginal**

we go:

Now to look at the formula for the **conditional** probability

we can look at the formula for

now to use an example, we will look back at our table.

let us look for the **conditional** probability of:

Thus, the probability that