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Scaling Units

The table below gives a rough idea of the units to use when setting up numeric scales for graphs.  As you gain experience in setting up numeric scales, you may decide that a situation requires smaller units or larger units than those given by this table. 

The data range is the maximum data value minus the minimum data value.  The classes for Data Range do overlap which means that you have two options for the units to use at the endpoints. The last three rows give the general setup: you determine the correct exponent  n  and the class containing the range of your data values, and the units are given by the corresponding value in the righthand column.   

Data Range

Units

0.07 to 0.14

0.01

0.14 to 0.30

0.02

0.30 to 0.70

0.05

0.7 to 1.4

0.1

1.4 to 3.0

0.2

3.0 to 7.0

0.5

7 to 14

1

14 to 30

2

30 to 70

5

70 to 140

10

140 to 300

20

300 to 700

50

700 to 1400

100

1400 to 3000

200

3000 to 7000

500

0.7 x 10 n to 1.4 x 10 n

1 x 10 n–1

1.4 x 10 n to 3.0 x 10 n

2 x 10 n–1

3.0 x 10 n to 7.0 x 10 n

5 x 10 n–1

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