Consider the following statements w.r.t the Titanic:
Assumption 1: Only men and women were on the ship
Assumption 2: There were a large number of men as well as women
Statement 1: 90 percent of all women survived
Statement 2: 90 percent of all those who survived, were women
The first indicates that saving women was probably of high priority (irrespective of whether saving men was)
When is the second statistic useful?
Can we say that one of them is almost always more useful than the other?
Note: Please suggest more appropriate tags (Thanks kjetil)