The left side shows a set of 30 objects varying in color (red, blue, and purple) and shape (X and O). One of the objects is to be chosen at random. The various possible conditional probabilities are shown below the objects. Click on one to see how the conditional probability is computed. For example, if you click on P(X|Red) which is read "the probability of X given Red" then a box is put around each of the red objects. Of these, those that are X's are shaded. The probability of X given it is red is the number of red X's (shaded boxes) divided by the total red items (the number of boxes).

Click "Another Example" for distribution of objects.