Specifications

Appendix A. Glossary
A-10
weather tight describes an instrumentation enclosure impenetrable by
common environmental conditions. During extraordinary weather events,
however, seals on the enclosure may be breached.
XML Extensible Markup Language.
A.2 Concepts
A.2.1 Accuracy, Precision, and Resolution
Three terms often confused are accuracy, precision, and resolution. Accuracy
is a measure of the correctness of a single measurement, or the group of
measurements in the aggregate. Precision is a measure of the repeatability of a
group of measurements. Resolution is a measure of the fineness of a
measurement. Together, the three define how well a data acquisition system
performs. To understand how the three relate to each other, consider “target
practice” as an analogy. The figure below shows four targets. The bull’s eye
on each target represents the absolute correct measurement. Each shot
represents an attempt to make the measurement. The diameter of the projectile
represents resolution.
The objective of a data acquisition system should be high accuracy, high
precision, and to produce data with resolution as high as appropriate for a given
application.