A more precise tolerance interval is more useful and more informative. If a tolerance interval is not sufficiently precise, it can be too wide and include a much larger percentage of the population than you specify. You can useto help you determine the precision of your tolerance intervals.
Suppose that p% is the targeted minimum percentage of the population for a tolerance interval. The following statistics define the precision of the tolerance interval:
Suppose you want to calculate a tolerance interval that covers 90% of the population. Using the default margin of error probability of 0.05 (5%), you determine that the margin of error for the interval is 2%. Together, these statistics indicate that there is only a 5% chance that your interval will include 92% or more of the population.