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