Statistical Values

Actual Percent Out of Specification Limits (ActPercentOut
ofSL)

The actual percentage of data that falls outside of specification limits.

Total number of result records outside of specification limits/Total number of individual result records

C Chart

Specifies how standard deviation for the C Chart is calculated.

NormalSample-
Size is the size configured for a characteristic.

ū is the value calculated for UBar.

DPMO Chart

Specifies how standard deviation for the DPMO Chart is calculated.

NormalSample-
Size is the size configured for a characteristic.

NumDefectOps is the num_defect_opp configured for a characteristic.

ū is the value calculated for UBar.

Defects per Million Opportunities (DPMO)

Specifies the average count of defects for every 1 million opportunities, where a single unit may have more than 1 opportunity for a specific defect. This value is only applicable for counted attribute characteristics.

N is the number of results data for a characteristic.

NumDefectOps is the value the user enters for number of defect opportunities.

Fraction Defective

Specifies the ratio of defects to sample size, for a single sample point.

Lower Reasonable Limit (LRL)

Specifies the lower reasonable limit for a specification that is obtained from the most recent sample.

Target – ((Target – LSL) x LRV)

if lrv_is_mult is True, and LSL is not null; otherwise, LRL = LRV.

LSL is the lower specification limit.

LRV is the value configured by the user.

Moving Average

Specifies the average of individual readings from a number of consecutive individual readings.

s is the moving average span configured for a characteristic.

is the individual result data.

is the moving average for sample i.

i is the number of the sample to which the moving average value is assigned. i is always less than or equal to N – s + 1, where N represents the number of individual values.

Moving Average Bar
()

Specifies the average of moving averages.

N is the number of results data.

is the moving average value for sample i.

i is the number of the sample to which the moving range value is assigned.

s is the moving average span configured for a characteristic.

Moving Range

Specifies the difference between the highest and lowest individual readings among a number of consecutive individual readings.

s is the moving average span configured for a characteristic.

is the individual result data, where k ranges from i to i + s – 1.

i is the number of the sample to which the moving range value is assigned. i is always less than or equal to N – s + 1, where N represents the number of individual values.

Moving Sigma

Specifies the standard deviation (σ) from a number of consecutive individual readings.

s is the moving average span configured for a characteristic.

is the individual result data.

i is the number of the sample to which the moving sigma value is assigned. i is always less than or equal to N – s + 1.

represents the mean calculated from the set of individual readings used to calculate the moving sigma.

NP Chart

Specifies how standard deviation for the NP chart is calculated.

NormalSample-
Size is the size configured for a characteristic.

is the value calculated for PBar.

NPBar and CBar ( and )

Specifies the average for binary and counted attribute characteristics as a count.

N is the number of results data for a characteristic.

i is the number of sample from which the Number of ((Defectives)/ (Defects)) and actual sample size are obtained.

PBar and UBar ( and )

Specifies the average for binary and counted attribute characteristics as a ratio to sample size.

N is the number of results data for a characteristic.

i is the number of sample from which the Number of ((Defectives)/
(Defects)) and actual sample size are obtained.

P Chart

Specifies how standard deviation for the P Chart is calculated.

NormalSample-
Size is the size configured for a characteristic.

is the value calculated for PBar.

Process Capability Index (Cp)

Specifies the process capability index, which is based on the upper and lower specification limits.

When USL and LSL contain non-null values:

When USL or LSL is null for a characteristic:

is the estimated standard deviation.

Process Capability Index (CpK)

Specifies the process capability index accounting for the sample mean, which is based on the upper and lower specification limits.

When USL and LSL contain non-null values:

When USL contains a non-null value, but LSL contains a null value:

When LSL contains a non-null value, but USL contains a null value:

USL is the upper specification limit.

LSL is the lower specification limit.

is the arithmetic mean.

is the estimated standard deviation.

Cp is the process capability index.

Process Performance Index (Pp)

Specifies the process performance index, which is based on the upper and lower specification limits.

When USL and LSL contain a non-null value:

When either the USL or the LSL contain a null value:

USL is the upper specification limit.

LSL is the lower specification limit.

σ is the standard deviation.

Process Performance Index (PpK)

Specifies the process performance index accounting for the sample mean, which is based on the upper and lower specification limits.

When USL and LSL contain non-null values:

When USL contains a non-null value, but LSL contains a null value:

When LSL contains a non-null value, but USL contains a null value:

USL is the upper specification limit.

LSL is the lower specification limit.

is the arithmetic mean.

σ is the standard deviation.

Pp is the process performance index.

Range

Specifies the range between the highest and the lowest data points.

Maximum Individual Reading – Minimum Individual Reading

Range Average of Subgroups (RBar)

Specifies the average range of values from various samples of equal size.

is the individual range among each sample or the moving range between two consecutive samples.

S is the total number of samples used for calculating the process statistics.

Sample Average (Mean)

Specifies the average of a set of data.

is the arithmetic mean.

N is the number of values (individual readings).

is each data element.

The arithmetic mean is calculated from the set of individual readings.

Standard Deviation (StdDev)

Specifies the statistical measure of spread or variability. Applies only to variable-type characteristics. The C chart, U chart, DPMO chart, P chart, and NP chart mentioned below are part of the Standard Deviation.

N is the number of results data.

is the individual result data.

is the arithmetic mean obtained from the results data.

U Chart

Specifies how standard deviation for the U Chart is calculated.

NormalSample-
Size is the size configured for a characteristic.

is the value calculated for UBar.

Upper Reasonable Limit (URL)

Specifies the upper reasonable limit for a specification that is obtained from the most recent sample.

if urv_is_mult is True, and USL is not null; otherwise, URL = URV.

USL is the upper specification limit.

URV is the value configured by the user.