Keypoints

• the functions table() and prop.table() can be used effectively to calculate probabilities, joint probabilities and conditional probabilities on the basis of real data.

• values for #P(A^c)#, #P(A \cap B)#, #P(A \cup B)# can often be obtained directly from the prop.table() output, but alternatively be calculated from other probabilities using the basic probability equations

• if a conditional probability (#P(A|B)#) is not directly available from data, it can be calculated with Bayes law #P(A|B)= \frac{P(B|A)P(A)}{P(B)}#