Methods and formulas for observed performance in Nonnormal Capability Analysis

PPM < LSL for Observed Performance

The number of parts out of one million that have measurements that are less than the lower specification limit is calculated as follows:

Notation

TermDescription
LSLLower specification limit
NTotal number of observations

PPM > USL for Observed Performance

The number of parts out of one million that have measurements that are greater than the upper specification limit is calculated as follows:

Notation

TermDescription
USLUpper specification limit
NTotal number of observations

PPM Total for Observed Performance

The total number of parts out of a million that are outside the specification limits is calculated as follows:

Notation

TermDescription
LSLLower specification limit
USLUpper specification limit
NTotal number of observations
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