prize7-8, Exercise 3: Class breaks change the story

Model answer (worked example with invented numbers):

Ten districts have these values (say, cases per 1,000 people): 2, 3, 4, 5, 6, 7, 8, 9, 10, 40.

Map A, three equal-width classes (2-15, 16-28, 29-40):
- Nine districts fall in the lowest class and one in the highest.
- The map looks calm with one severe hotspot.

Map B, three classes with equal numbers of districts (about 3-4 in each: 2-4, 5-7, 8-40):
- The districts are spread across all three colours.
- The map looks as if there is a broad gradient of risk, and the hotspot disappears into the top class with 8 and 9.

Map C, breaks chosen at 5 and 9 to highlight "high" as 10 and above:
- Only two districts are in the top class.

Lesson: the same data, with different breaks, tells three different stories. Always state the breaks in the legend, and consider showing the data in more than one way.