You can select which clearance is taken into account for the calculation. For interference fit and clearance a range of tolerances is given. The calculation can either use the minimum, minimum probable, medium, maximum probable or maximum value of the clearance. For other needs, the operating clearance can be specified directly as a number.
The probable values are calculated assuming a normal distribution within the tolerance field and an independence of tolerances for inner ring fit, outer ring fit and bearing clearance. In addition linearity is assumed which is not true in case a fit changes from interference to clearance within the tolerance range. For comparison probable values could be calculated using the statistical parameter variation.