The goal of the Laboratory Test is to produce actual data about a Sample of real material.
The numbers that come from a Laboratory Test are represented in Figure 17-5 as Direct Measurements from a Laboratory Test. That is, each instance of Direct Measurement must be from one Laboratory Test, and it provides a value for the attribute, Value Quantity.
Alternatively, a person may simply look at the Sample and observe things like “color”, “cloudiness”, and other visible characteristics. This second approach is recorded as a second kind of Observation—a Physical Observation.
In either case, the Observation must be of a single Parameter. A Parameter is “an(especially measurable or quantifiable) characteristic or feature”