An independent testing laboratory uses a four-step process to analyze content purity of product samples sent to the lab by chemical manufacturers. Each step of this process requires a testing machine that must be calibrated to ensure it provides reliably accurate results because unreliable results at any step of the process decreases the reliability of results for the entire process. The laboratory's scientific director overseeing this process set a standard of total process reliability at 0.93 or 93%. Each week lab personnel run calibration tests to ensure each machine's reliability will allow for this. The diagram below depicts the four testing machines used in this process and shows the most recent week's estimates of each machine's reliability