5.3 The procedures defined in this guide can be used to estimate the accuracy and precision of an online analyzer, (1) to conduct acceptance testing following installation and (2) to monitor the accuracy and precision (a) during routine use (quality control), (b) when significant changes are made to the analyzer, and (c) when a significant change in the coal being analyzed occurs (e.g., a different seam at a mine, or a new coal source at a power plant). These procedures can also be used for calibration purposes.