The number of digits reported for a quantity should reflect its precision and trustworthiness. For example:

• if a document is reporting the range in leaf length for a species, and many measurements have been taken in tenths of centimetres, give the range in tenths of centimetres
• weights measured with a scale accurate to 0.1 g should be reported in tenths of grams, not hundredths of grams
• percentages based on small sample sizes (<100) should be reported as whole numbers; expressing them to 1 decimal place probably has little scientific value and can be distracting to the reader.

Calculated values (eg means) based on raw measurements should be reported to a maximum of 1 significant digit past the accuracy of the original measurement:

When rounding a number to a certain number of significant digits, leave the digit unchanged if the digit to the right of the last significant digit is below 5, but increase it by 1 if the digit to the right of the last significant digit is equal to or above 5. For a number rounded to 3 significant digits: