kstats-core/org.oremif.kstats.descriptive/SpcConstants

SpcConstants

data class SpcConstants(val a2: Double, val a3: Double, val d3: Double, val d4: Double, val b3: Double, val b4: Double, val c4: Double)(source)

Standard Statistical Process Control (SPC) constants for a given subgroup size.

These constants are used to compute control limits for x-bar, R, and S control charts. They are derived from the sampling distribution of the range and standard deviation of normally distributed data. Values are tabulated for subgroup sizes 2 through 25.

Example:

val c = spcConstants(5)
c.a2  // 0.577 — used for x̄-R chart limits
c.a3  // 1.427 — used for x̄-S chart limits
c.c4  // 0.9400 — bias-correction factor for sample standard deviation

Constructors

SpcConstants

constructor(a2: Double, a3: Double, d3: Double, d4: Double, b3: Double, b4: Double, c4: Double)

Properties

val a2: Double

factor for computing x-bar chart control limits from the mean range (R-bar).

val a3: Double

factor for computing x-bar chart control limits from the mean standard deviation (S-bar).

val b3: Double

factor for computing the lower control limit of the S chart. Zero for small subgroup sizes.

val b4: Double

factor for computing the upper control limit of the S chart.

val c4: Double

bias-correction factor that relates the expected sample standard deviation to the population standard deviation for normally distributed data.

val d3: Double

factor for computing the lower control limit of the R chart. Zero for small subgroup sizes.

val d4: Double

factor for computing the upper control limit of the R chart.

SpcConstants

Example:

See also

Constructors

Properties