Often, simply understanding totals, sums, and even the breakdown of part-to-whole only gives you a piece of the overall picture. Many times, you'll want to understand where individual items fall within a distribution of all similar items.
You might find yourself asking questions like these:
- How long do most of our patients stay in the hospital? Which patients fall outside the normal range?
- What's the average life expectancy for components in a machine and which components fall above or below that average? Are there any components with extremely long or extremely short lives?
- How far above or below "passing" were most students' test scores?
These questions all have similarities. In each case, you are asking for an understanding ...