Zlt

For long-term data, Z_LT = Z_TOTAL, expressed as Zlt-total,

where

Z_TOTAL =

and

is the inverse normal cumulative distribution function, which assumes a right-sided tail.

In Microsoft Excel:

When displaying long-term metrics, Z_LT appears as Zlt-total. This metric is equal to Z-LSL if there is only a lower specification limit or Z-USL if there is only an upper specification limit.

For short-term data, Z_LT = Z_ST - ZScoreShift. When displaying short-term metrics, Z_LT appears in the capability metrics table as Zlt.

Note:

Z scores typically are reported only for normal data. The maximum value for Z scores calculated by Crystal Ball from forecast data is 21.18.