For reporting the amount retained by wash, how should it be reported if less than 10%?

When reporting the amount retained by wash, especially when it is less than 10%, the value should be reported to the nearest tenth of a percent. This level of precision is appropriate in construction materials testing because it accurately reflects small variations in the amount retained, which can be significant in terms of material properties.

Reporting to the nearest tenth allows for a sensible degree of accuracy without overwhelming precision that is unnecessary for low percentages. For example, if the amount retained from a wash is calculated to be 7.2%, this level of specificity provides useful information for evaluating the material while being straightforward for readers to understand.

The other reporting methods would not be appropriate in this case. Reporting to the nearest whole number could lead to a loss of meaningful detail, particularly for very small amounts. Reporting to two decimal places might be overly precise for values under 10%, where such exactness doesn't contribute significant insight. Simply labeling the amount as a percentage without adhering to a defined standard of precision could create confusion and inconsistency in data reporting. Thus, rounding to the nearest tenth of a percent strikes a balance between clarity and accuracy for amounts retained that are less than 10%.