Decimal Format
18.4.2 Decimal Format
The decimal format is recommended for numbers used with units of measure. Numerical values less than 1 require placement of 0 before the decimal marker.
Preferred: |
0.123 |
Avoid: |
.123 |
However, certain statistical values, such as α levels and P values, should be reported without the use of 0 before the decimal marker. (See 19.7.1, Numbers and Percentages, Forms of Numbers, Decimals; and 20.9, Study Design and Statistics, Glossary of Statistical Terms.)
The sample size was based on detecting a 10% difference in the primary outcome measure, using a 2-sided α level of .05.
Statistical significance was defined as P < .01.
Fractions should not be used with SI units.
Preferred: |
2.5 kg |
Avoid: |
2½ kg |
Mixed fractions occasionally are used in text to indicate less precise measurements and most commonly involve units of measure representing time.
After more than 7½ years of investigation, the effort to develop a new vaccine was abandoned.
The decimal format also could be used:
After more than 7.5 years of investigation, the effort to develop a new vaccine was abandoned.