Use tolerance intervals to compute a range of values for a product's characteristic that likely covers a specified proportion of future product output. A tolerance interval defines the upper and/or lower bounds within which a certain percent of the process output falls with a stated confidence.
To generate tolerance intervals, you must specify both a minimum percentage of the population and a confidence level. Traditionally, both values are close to 100. The percentage is the minimum percentage of the population that you want the interval to cover. The confidence level is the likelihood that an interval will actually cover the minimum percentage.
Minitab uses defaults of 95% for both confidence level and minimum percentage of population in the interval.