In Example 8b,  Show that Y1,..., Yk, Yk+1 are exchangeable. Note that Yk+1 is the number...

In Example 8b,  Show that Y1,..., Yk, Yk+1 are exchangeable. Note that Yk+1 is the number of balls one must observe to obtain a special ball if one considers the balls in their reverse order of withdrawal.