Statistics

A statistics window displays the textual report produced by an analysis. Although each analysis produces different chart and statistics windows, the windows themselves behave in the same way. Here is a detailed statistics report for a Combined Repeatability Analysis.

Note the table highlighted below, which is useful for summarizing the R&R measurement error. The third row, %R&R, shows the percentage of total R&R due to each component: Repeatability and Reproducibility, whose sum (total R&R) is 100%. The fourth row, % Process Variation, compares the R&R error to the estimated variation in the process. When this is large, it impacts your ability to measure process variation using SPC control charts. The last row, % Tolerance, compares the R&R error to your specifications. If large, you are accepting bad parts and rejecting good parts.