Tolerance intervals are a range of values for a specific quality characteristic of a product that likely covers a specified minimum percentage of current or future product output. Use Tolerance Intervals (Nonnormal Distribution) to determine the range within which a specified minimum proportion of the process measurements is expected to fall when your data come from a specified nonnormal distribution.
For example, a manufacturer wants to evaluate the variability of their paper bleaching process. The brightness of the pulp varies from one batch to the next. The manufacturer uses a two-sided 95% tolerance interval to determine the range within which the brightness of at least 99% of the batches are expected to fall.
To perform a tolerance interval analysis, choose .
If you want to calculate tolerance intervals when your data come from a normal distribution, use normal tolerance intervals.